Amplifier system

Claim 2

A wide dynamic range automatic high-speed gain ranging amplifier system comprising a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit, means defining a comparator circuit for comparing a signal coupled to an input circuit thereof with a predetermined reference signal, sampling means for momentarily coupling the respective outputs of said amplifier stages to said comparator circuit during respective sampling intervals occurring in time sequence, means responsive to said comparator circuit for selectively maintaining one of said amplifier stage output circuits coupled to said common output circuit for at least a predetermined minimum holding time interval when the output signal sampled at said one of said amplifier stage output circuits bears a predetermined relationship to said reference signal.

Claim 3

Apparatus as defined in claim 1 further comprising analog-to-digital converter means coupled to said common output for converting an analog signal appearing at said output during said holding time interval to a digital signal of corresponding value, and means for indicating which one of said amplifier stage output circuits is coupled to said common output circuit in correlation with the value of said digital signal.

Claim 4

A wide dynamic range automatic high-speed gain ranging amplifier system comprising a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage is coupled to the respective input circuit of the next following amplifier stage of the cascade circuit, a common output circuit, means including a plurality of normally open switch means for selectively coupling the respective outputs of said amplifier stages to said common output circuit, means defining a comparator circuit coupled to said common output circuit for comparing a signal appearing at said common output circuit with a predetermined reference signal, sequencing means for momentarily closing said switch means in time sequence for sequentially coupling the respective outputs of said amplifier stages to said comparator circuit and means responsive to said comparator circuit for selectively maintaining one of said switch means in its closed position when the output signal coupled through said one switch means to said common output circuit bears a predetermined relationship to said reference signal.

Claim 5

A wide dynamic range automatic high-speed gain ranging amplifier system comprising a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage is coupled to the respective input circuit of the next following amplifier stage of the cascade circuit, a common output circuit, means including a plurality of normally open switch means for selectively coupling the respective outputs of said amplifier stages to said common output circuit, means defining a comparator circuit coupled to said common output circuit for comparing a signal appearing at said common output circuit with a predetermined reference signal, sequencing means for momentarily closing said switch means in time sequence for sequentially coupling the respective outputs of said amplifier stages to said comparator circuit and means responsive to said comparator circuit for selectively maintaining one of said switch means in its closed position when the output signal coupled through said one switch means to said common output circuit bears a predetermined relationship to said reference signal.

Claim 6

Apparatus as defined in claim 3 further comprising high-speed amplifier and impedance matching means coupled in circuit between said normally open switching means and the means defining said common output circuit.

Claim 7

A wide dynamic range automatic high-speed gain ranging amplifier system comprising a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit, means defining a comparator circuit for comparing a signal coupled to an input circuit thereof with a predetermined reference signal, sampling means for momentarily coupling the respective outputs of said amplifier stages to said comparator circuit in timed sequence, means responsive to said comparator circuit for selectively maintaining one of said amplifier stage output circuits coupled to said common system output circuit when the output signal sampled at said one of said amplifier stage output circuits bears a predetermined relationship to said reference signal.

Claim 8

A wide dynamic range automatic high-speed gain ranging amplifier system comprising a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit, means defining a comparator circuit for comparing a signal coupled to an input circuit thereof with a predetermined reference signal, sampling means for momentarily coupling the respective outputs of said amplifier stages to said comparator circuit in timed sequence, means responsive to said comparator circuit for selectively maintaining one of said amplifier stage output circuits coupled to said common system output circuit when the output signal sampled at said one of said amplifier stage output circuits bears a predetermined relationship to said reference signal.

Claim 9

A wide dynamic range automatic high-speed gain ranging amplifier system comprising a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stAge is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit, means defining a comparator circuit for comparing a signal coupled to an input circuit thereof with a predetermined reference signal, sampling means for momentarily coupling the respective outputs of said amplifier stages to said comparator circuit in timed sequence, means responsive to said comparator circuit for selectively maintaining one of said amplifier stage output circuits coupled to said common output circuit when the output signal sampled at said one of said amplifier stage output circuits bears a predetermined relationship to said reference signal, analog-to-digital converter means coupled to said common output for converting an analog signal appearing at said output to a digital signal of corresponding value, and means for indicating which one of said amplifier stage output circuits is coupled to said common output circuit in correlation with the value of said digital signal.

Claim 10

A wide dynamic range automatic high-speed gain ranging amplifier system comprising a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stAge is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit, means defining a comparator circuit for comparing a signal coupled to an input circuit thereof with a predetermined reference signal, sampling means for momentarily coupling the respective outputs of said amplifier stages to said comparator circuit in timed sequence, means responsive to said comparator circuit for selectively maintaining one of said amplifier stage output circuits coupled to said common output circuit when the output signal sampled at said one of said amplifier stage output circuits bears a predetermined relationship to said reference signal, analog-to-digital converter means coupled to said common output for converting an analog signal appearing at said output to a digital signal of corresponding value, and means for indicating which one of said amplifier stage output circuits is coupled to said common output circuit in correlation with the value of said digital signal.

Claim 11

A seismic signal processing system comprising a plurality of signal channels, each of said channels comprising a wide dynamic range automatic high-speed gain ranging amplifier system including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage of the channel is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit for seismic system, means defining a comparator circuit for comparing a signal coupled to an input circuit thereof with a predetermined reference signal, sampling means for momentarily coupling the respective outputs of the cascaded amplifier stages of each of said channels to said common output circuit in timed sequence, means responsive to said comparator circuit for selectively maintaining one of said amplifier stage output circuits coupled to said common output circuit for at least a predetermined holding time interval when the output signal sampled at said one of said amplifier stage output circuits bears a predetermined relationship to said reference signal, analog-to-digital converter means coupled to said common output for converting an analog signal appearing at said common output during said holding time to a first digital signal of corresponding value, said converter being characterized by the capability of converting to digital form an analog signal applied thereto for said predetermined time interval, means for providing a second digital signal indicating which one of said amplifier stage output circuits is coupled to said common output circuit at least during times when one of said amplifier stage outputs is maintained coupled to said common output circuit, and means for recording signal information corresponding to said first digital signal in correlation with signal information corresponding to said second digital signal.

Claim 12

A seismic signal processing system comprising a plurality of signal channels, each of said channels comprising a wide dynamic range automatic high-speed gain ranging amplifier system including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage of the channel is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit for seismic system, means defining a comparator circuit for comparing a signal coupled to an input circuit thereof with a predetermined reference signal, sampling means for momentarily coupling the respective outputs of the cascaded amplifier stages of each of said channels to said common output circuit in timed sequence, means responsive to said comparator circuit for selectively maintaining one of said amplifier stage output circuits coupled to said common output circuit for at least a predetermined holding time interval when the output signal sampled at said one of said amplifier stage output circuits bears a predetermined relationship to said reference signal, analog-to-digital converter means coupled to said common output for converting an analog signal appearing at said common output during said holding time to a first digital signal of corresponding value, said converter being characterized by the capability of converting to digital form an analog signal applied thereto for said predetermined time interval, means for providing a second digital signal indicating which one of said amplifier stage output circuits is coupled to said common output circuit at least during times when one of said amplifier stage outputs is maintained coupled to said common output circuit, and means for recording signal information corresponding to said first digital signal in correlation with signal information corresponding to said second digital signal.

Claim 13

Apparatus as defined in claim 7 wherein the means for momentarily coupling the respective outputs of said amplifier stages to said comparator circuits in timed sequence comprises a digital control and multiplexer network coupled to the means for selectively maintaining one of said amplifier stage output circuits coupled to said common output circuit.

Claim 14

Apparatus as defined in claim 7 wherein said sampling means for momentarily coupling said outputs of said amplifier stages to said amplifier circuits in timed sequence comprises a digital control network coupled to the means responsive to said comparator circuit for selectively maintaining one of said amplifier stage output circuits coupled to said common output circuit and a channel multiplexer for selectively coupling the respective outputs of said channels to the common output circuit in timed sequence.

Claim 15

A signal-processing system comprising a wide dynamic range automatic high-speed gain raNging amplifier system including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage of the cascade circuit is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit, means defining a comparator circuit for comparing a signal coupled to an input circuit thereof with a predetermined reference signal, sampling means for momentarily coupling the respective outputs of the cascaded amplifier stages to said common output circuit in timed sequence, means responsive to said comparator circuit for selectively maintaining one of said amplifier stage output circuits coupled to said common output circuit for at least a predetermined holding time interval when the output signal sampled at said one of said amplifier stage output circuits bears a predetermined relationship to said reference signal, analog-to-digital converter means coupled to said common output for converting an analog signal appearing at said common output during said holding time to a first digital signal of corresponding value, said converter being characterized by the capability of converting to digital form an analog signal applied thereto for said predetermined time interval, means for providing a second digital signal indicating which one of said amplifier stage output circuits is coupled to said common output circuit at least during times when one of said amplifier stage outputs is maintained coupled to said common output circuit, and means for recording signal information corresponding to said first digital signal in correlation with signal information corresponding to said second digital signal.

Claim 16

A signal-processing system comprising a wide dynamic range automatic high-speed gain raNging amplifier system including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage of the cascade circuit is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit, means defining a comparator circuit for comparing a signal coupled to an input circuit thereof with a predetermined reference signal, sampling means for momentarily coupling the respective outputs of the cascaded amplifier stages to said common output circuit in timed sequence, means responsive to said comparator circuit for selectively maintaining one of said amplifier stage output circuits coupled to said common output circuit for at least a predetermined holding time interval when the output signal sampled at said one of said amplifier stage output circuits bears a predetermined relationship to said reference signal, analog-to-digital converter means coupled to said common output for converting an analog signal appearing at said common output during said holding time to a first digital signal of corresponding value, said converter being characterized by the capability of converting to digital form an analog signal applied thereto for said predetermined time interval, means for providing a second digital signal indicating which one of said amplifier stage output circuits is coupled to said common output circuit at least during times when one of said amplifier stage outputs is maintained coupled to said common output circuit, and means for recording signal information corresponding to said first digital signal in correlation with signal information corresponding to said second digital signal.

Claim 17

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network, means for time-sequentially sampling a signal translated through said network to said common output under said progressively different gain ranges, said sampling means including means for switching progressively from one of said amplifier gain ranges to another of said ranges, means defining a comparator circuit having an input coupled to said common output for comparing a signal sampled at said common output circuit with a predetermined reference signal, means responsive to said comparator circuit for selectively maintaining one of said predetermined amplifier gain ranges for at least a predetermined minimum holding time interval when the output signal sampled at said common output bears a predetermined relationship to said reference signal.

Claim 18

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network, means for time-sequentially sampling a signal translated through said network to said common output under said progressively different gain ranges, said sampling means including means for switching progressively from one of said amplifier gain ranges to another of said ranges, means defining a comparator circuit having an input coupled to said common output for comparing a signal sampled at said common output circuit with a predetermined reference signal, means responsive to said comparator circuit for selectively maintaining one of said predetermined amplifier gain ranges for at least a predetermined minimum holding time interval when the output signal sampled at said common output bears a predetermined relationship to said reference signal.

Claim 19

Apparatus as defined in claim 11 wherein the means for establishing said plurality of progressively different predetermined amplifier gain ranges includes a plurality of switching means coupled in circuit with successive amplifier stages of said cascade circuit.

Claim 20

Apparatus as defined in claim 11 wherein said means for establishing said plurality of progressively different amplifier gain ranges comprises switching means for selectively deriving an output signal amplified by a progressively different number of said cascade amplifier stages.

Claim 21

Apparatus as defined in claim 10 wherein said first and second digital signals are in the form of a floating point digital word comprising a mantissa and an exponent in the form: Q + or - xb k; wherein Q rEpresents the magnitude of the amplitude of the input signal to said signal-processing system; wherein b represents the gain of each one of the cascaded amplifier stages; wherein x, the mantissa, represents the first digital signal which corresponds to the output amplitude of a particular one of the cascaded amplifier stages selected by the signal sampling means; wherein k, the exponent, represents the second digital signal which corresponds to the number of said cascaded amplifier stages through which the particular input signal is translated in order to arrive at the selected cascade amplifier stage output determined by the sampling means.

Claim 22

Apparatus as defined in claim 14 wherein said cascaded amplifier stages have a common amplification base b such that the exponents of each such cascaded stage are algebraically additive to form the value of said exponent corresponding to said second digital signal.

Claim 23

Apparatus as defined in claim 1 wherein said plurality of cascaded amplifier stages have an overall DC gain of substantially unity at said common output circuit and an overall AC gain which is significantly greater than unity.

Claim 24

Apparatus as defined in claim 16 wherein the DC gain of each of said cascaded amplifier stages is substantially unity, whereby the overall DC gain of said plurality of cascaded stages is substantially unity.

Claim 25

Apparatus as defined in claim 10 wherein said plurality of cascaded amplifier stages have an overall DC gain of substantially unity at said common output circuit and an overall AC gain which is significantly greater than unity.

Claim 26

Apparatus as defined in claim 18 wherein said DC gain of each of said cascaded amplifier stages is substantially unity, whereby the overall DC gain of said plurality of cascaded stages is substantially unity.

Claim 27

Apparatus as defined in claim 11 wherein the network comprising said plurality of cascaded amplifier stages has an overall DC gain of substantially unity at said common output circuit and an overall AC gain which is significantly greater than unity.

Claim 28

Apparatus as defined in claim 20 wherein the DC gain of each of said cascaded amplifier stages is substantially unity, whereby the overall DC gain of said plurality of cascaded stages is substantially unity.

Claim 29

Apparatus as defined in claim 10 characterized by an operating cycle which is completed within the signal cycle of an amplifier system input signal of predetermined frequency, said operating cycle including the functioning of the means for momentarily coupling the respective outputs of the cascaded amplifier stages to said common output circuit and for selectively maintaining one of said amplifier stage output circuits coupled to said output for said predetermined time interval required for said analog-to-digital converter means to sample an analog signal for conversion to a first digital signal.

Claim 30

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network, means for time sequentially switching progressively from one to another of said predetermined gain ranges during successive sampling intervals, a comparator circuit adapted to compare a signal applied to an input thereof with a predetermined reference, means including said comparator circuit for comparing with said reference signals translated by said amplifier network to said common output during said sampling intervals as said amplifier network is switched Progressively through said predetermined gain ranges, and means for selectively holding one of said predetermined gain ranges for at least a predetermined holding time interval when the output signal sampled at said common output bears said predetermined relationship to said reference.

Claim 31

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship whereby the respective output circuit of each successive amplifier stage is coupled to the respective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network, means for time sequentially switching progressively from one to another of said predetermined gain ranges during successive sampling intervals, a comparator circuit adapted to compare a signal applied to an input thereof with a predetermined reference, means including said comparator circuit for comparing with said reference signals translated by said amplifier network to said common output during said sampling intervals as said amplifier network is switched Progressively through said predetermined gain ranges, and means for selectively holding one of said predetermined gain ranges for at least a predetermined holding time interval when the output signal sampled at said common output bears said predetermined relationship to said reference.

Claim 32

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network, means for time sequentially switching progressively from one to another of said predetermined gain ranges during successive sampling time intervals, means comprising a comparator for comparing signals translated to said common output during said sampling intervals with a predetermined reference, means responsive to said comparator for selecting one of said gain ranges when said sampled output bears a predetermined relationship to said reference signal and for holding said predetermined gain range for at least a predetermined holding time interval while the sampled signal at said common output during said holding time interval is translated to said common output as a first signal and means for deriving a second signal indicating which one of said predetermined gain ranges is selected for a given holding time interval.

Claim 33

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network, means for time sequentially switching progressively from one to another of said predetermined gain ranges during successive sampling time intervals, means comprising a comparator for comparing signals translated to said common output during said sampling intervals with a predetermined reference, means responsive to said comparator for selecting one of said gain ranges when said sampled output bears a predetermined relationship to said reference signal and for holding said predetermined gain range for at least a predetermined holding time interval while the sampled signal at said common output during said holding time interval is translated to said common output as a first signal and means for deriving a second signal indicating which one of said predetermined gain ranges is selected for a given holding time interval.

Claim 34

Apparatus as defined in claim 24 wherein said first signal is in analog form and wherein said apparatus further comprises analog-to-digital converter means coupled to said common output for converting said analog first signal to a corresponding digital first signal and wherein said predetermined holding time interval is at least as long as the characteristic minimum time required for said converter to sample said analog signal to a corresponding digital signal for conversion.

Claim 35

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network, means for time sequentially switching progressively from one to another of said predetermined gain ranges during successive sampling time intervals, means responsive to signals translated to said common output during said sampling intervals for selecting one of said gain ranges when said sampled output bears a predetermined value and for holding the said selected one of predetermined gain ranges for at least a predetermined holding time interval while the sampled signal at said common output during said holding time interval is translated to said common output during said holding time interval as a first signal and means for deriving a second signal indicating which one of said predetermined gain ranges is selected for a given holding time interval.

Claim 36

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network, means for time sequentially switching progressively from one to another of said predetermined gain ranges during successive sampling time intervals, means responsive to signals translated to said common output during said sampling intervals for selecting one of said gain ranges when said sampled output bears a predetermined value and for holding the said selected one of predetermined gain ranges for at least a predetermined holding time interval while the sampled signal at said common output during said holding time interval is translated to said common output during said holding time interval as a first signal and means for deriving a second signal indicating which one of said predetermined gain ranges is selected for a given holding time interval.

Claim 37

Apparatus as defined in claim 26 wherein said first signal is in analog form and wherein said apparatus further comprises analog-to-digital converter means coupled to said common output for converting said analog first signal to a corresponding digital first signal and wherein said predetermined holding time interval is at least as long as the characteristic minimum time required for said converter to sample said analog signal for conversion to a corresponding digital signal.

Claim 38

Apparatus as defined in claim 27 further comprising means for recording both said digital first signal corresponding to said first analog signal and a second digital signal corresponding to said second signal in digital form as a floating point word comprising a mantissa and an exponent in the form: Q + or - xb k; wherein Q represents the magnitude of the input sigNal to said amplifier system; wherein b represents the gain of the individual amplifier stages of said network through which the input signal is translated to the common output; wherein x, the mantissa, represents the first digital signal which corresponds to said first analog signal; wherein k, the exponent, represents the second digital signal corresponding to said second signal indicating the selected gain range of said network during said holding time interval.

Claim 39

Apparatus as defined in claim 26 characterized by an operating cycle for said means for selecting one of said gain ranges and for holding said selected gain range during said holding time interval which is completed within the signal cycle of an amplifier system input signal of predetermined frequency.

Claim 40

Apparatus as defined in claim 19 wherein the AC gain of each of said plurality of cascaded stages is a whole number greater than unity.

Claim 41

Apparatus as defined in claim 14 wherein k unity and wherein b a positive integer greater than unity.

Claim 42

Apparatus as defined in claim 14 wherein the alternating current amplification values of k unity and of b a positive whole number greater than unity and wherein the direct current amplification value of b unity.

Claim 43

Apparatus as defined in claim 32 wherein for alternating current amplification value of b 8.

Claim 44

Apparatus as defined in claim 4 wherein said high-speed amplifier and impedance matching means comprises a circuit having an input impedance which is at least of the order of 107 times the ''''ON'''' resistance of the normally open switching means coupled to its input.

Claim 45

Apparatus as defined in claim 34 wherein said normally open switching means comprises a solid state analog switch having a relatively high ''''OFF'''' resistance which is at least of the order 1010 ohms and a relatively low ''''ON'''' resistance.

Claim 46

Apparatus as defined in claim 3 further comprising respective phase adjusting means coupled in at least all but the longest of the respective signal paths including each of said respective amplifier stage outputs and said common output circuit.

Claim 47

Apparatus as defined in claim 36 wherein said phase adjustment means comprises an isolation stage adapted to block switching transients between the respective switch means and the input of the next following cascaded amplifier stage.

Claim 48

Apparatus as defined in claim 37 wherein said isolation stage further provides means for adjusting the DC level of the common output of respective switch elements in each of said paths.

Claim 49

Apparatus as defined in claim 11 wherein said means for time sequentially sampling a signal translated through said network to said common output under progressively different gain ranges comprises means for changing the gain of said network to the common output without changing the gain of the individual stages of said network.

Claim 50

Apparatus as defined in claim 11 wherein the means for sampling a signal translated through said network to said common output functions to achieve such sampling during times that are mutually exclusive with respect to times when said means for switching progressively from one of said amplifier gain ranges to another is in the process of accomplishing such switching.

Claim 51

Apparatus as defined in claim 14 wherein k unity and wherein b a positive number.

Claim 52

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges comprising a plurality of different circuit paths providing said progressively different amplifier gain ranges, means for time sequentially switching Progressively from one to another of said circuit paths during successive sampling time intervals, means responsive to signals translated through said circuit paths during said sampling intervals for selecting one of said circuit paths when said sampled output bears a predetermined value and for holding the selected circuit path for at least a predetermined holding time interval while the sampled signal is translated through said selected path to said common output as a first signal and means for deriving a second signal indicating which one of said circuit paths is selected for a given holding time interval.

Claim 53

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges comprising a plurality of different circuit paths providing said progressively different amplifier gain ranges, means for time sequentially switching Progressively from one to another of said circuit paths during successive sampling time intervals, means responsive to signals translated through said circuit paths during said sampling intervals for selecting one of said circuit paths when said sampled output bears a predetermined value and for holding the selected circuit path for at least a predetermined holding time interval while the sampled signal is translated through said selected path to said common output as a first signal and means for deriving a second signal indicating which one of said circuit paths is selected for a given holding time interval.

Claim 54

A seismic signal processing system as defined in claim 7, wherein each of said amplifier channels includes an active filter having a signal output coupled to the input circuit of the amplifier system of the respective channel.

Claim 55

An apparatus as defined in claim 10, wherein said signal processing system includes an active filter having a signal output coupled to the input of said amplifier system.

Claim 56

An amplifier system as defined in claim 23, wherein said system includes an active filter having a signal output coupled to the input of said amplifier network.

Claim 57

Apparatus as defined in claim 23, wherein said means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network comprises means for changing the gain of said network to the common output by progressively switching from one to another of said amplifier stages without changing the gain of the individual stages of said network.

Claim 58

Apparatus as defined in claim 24, wherein said means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network comprises means for changing the gain of said network to the common output by progressively switching from one to another of said amplifier stages without changing the gain of the individual stages of said network.

Claim 59

Apparatus as defined in claim 26, wherein said means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network comprises means for changing the gain of said network to the common output by progressively switching from one to another of said amplifier stages without changing the gain of the individual stages of said network.

Claim 60

Apparatus as defined in claim 29, wherein said means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network comprises means for changing the gain of said network to the common output by progressively switching from one to another of said amplifier stages without changing the gain of the individual stages of said network.

Claim 61

Apparatus as defined in claim 1, characterized in that said holding time interval is significantly longer than said sampling interval.

Claim 62

Apparatus as defined in claim 11, characterized in that said holding time interval is significantly longer than the sampling time interval.

Claim 63

Apparatus as defined in claim 23, characterized in that said holding time interval is significantly longer than said sampling time interval.

Claim 64

Apparatus as defined in claim 24, characterized in that said holding time interval is significantly longer than said sampling time interval.

Claim 65

Apparatus as defined in claim 26, characterized in that said holding time interval is significantly longer than said sampling time interval.

Claim 66

Apparatus as defined in claim 42, characterized in that said holding time interval is significantly longer than said sampling time interval.

Claim 67

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship, whereby the respective output circuit of each successive amplifier stage is coupled to the resPective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network, means operating recurrently during successive operating cycles of said amplifier system for time-sequentially switching during each of said operating cycles from one to another of said predetermined gain ranges during successive sampling intervals occurring in timed sequence, means for comparing a predetermined reference with signals translated by said amplifier network to said common output during said sampling intervals, means for converting an analog signal appearing at said common output to a corresponding digital signal, means for selecting one of said gain ranges when the output signal sampled at said common output bears a predetermined relationship to said reference, and means for deriving a second signal indicating which one of said predetermined gain ranges has been selected during the times that said signal at said common output is converted to a corresponding digital signal.

Claim 68

A wide dynamic range automatic high-speed gain ranging amplifier system comprising an amplifier network including a plurality of amplifier stages each having a respective input circuit and a respective output circuit, said amplifier stages being coupled in cascade circuit relationship, whereby the respective output circuit of each successive amplifier stage is coupled to the resPective input circuit of the next-following amplifier stage of the cascade circuit, a common output circuit for said network, means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network, means operating recurrently during successive operating cycles of said amplifier system for time-sequentially switching during each of said operating cycles from one to another of said predetermined gain ranges during successive sampling intervals occurring in timed sequence, means for comparing a predetermined reference with signals translated by said amplifier network to said common output during said sampling intervals, means for converting an analog signal appearing at said common output to a corresponding digital signal, means for selecting one of said gain ranges when the output signal sampled at said common output bears a predetermined relationship to said reference, and means for deriving a second signal indicating which one of said predetermined gain ranges has been selected during the times that said signal at said common output is converted to a corresponding digital signal.

Claim 69

A system as defined in claim 56, wherein said means for establishing a plurality of progressively different predetermined amplifier gain ranges for said amplifier network comprises means for sampling the respective outputs of successive ones of said amplifier stages during said successive sampling intervals.

Claim 70

A system as defined in claim 56, wherein said means for establishing a plurality of progressively different predetermined amplifier gain ranges comprises means for selectively switching the outputs of respective amplifiers in said network to said common output.

Claim 71

A system as defined in claim 57, wherein said means for establishing a plurality of progressively different predetermined amplifier gain ranges comprises means for selecting different gain paths without changing the gain of the individual amplifier stages of said network.

Claim 72

A system as defined in claim 57, wherein the means for switching from one to another of said gain ranges during said successive sampling intervals comprises means for progressively switching during each operating cycle from a beginning gain range which is a range at one end of said plurality of ranges.