Method of and means for gainranging amplification

Claim 3

The method of claim 1 including the step of limiting the maximum amplitude of the output of each of said cascaded stages of amplification to the same predetermined value.

Claim 4

The method of claim 2 wherein the output of said cascaded amplifier stages taken for said amplified output signal is that output of said cascaded amplifier stages having an unlimited maximum value nearest said predetermined value.

Claim 5

The method of claim 1 including the step of applying said combined signal to a display device for monitoring.

Claim 6

The method of claim 1 including the steps of taking a sample output from the first of said cascaded stages of amplification and adding said sample output to sample outputs taken from each subsequent odd numbered stage of amplification to produce a first combined signal, taking a sample output from the second of said cascaded stages of amplification and adding said sample output to sample outputs taken from each subsequent even stage of amplification to produce a second combined signal, shifting the phase of one of said combined signals by 180* and thereafter adding said first and second combined signals to produce said combined control signal.

Claim 7

The method of claim 1 including the step of subjecting said combined signal to full wave rectification prior to utilizing said combined signal to select the output of said cascaded amplifier stages taken for the amplified output signal.

Claim 8

The method of claim 1 including the step of filtering the output of the first of said plurality of stages of amplification to limit said output to a given frequency range.

Claim 9

Apparatus for amplifying an electrical input signal to provide an amplified electrical output signal comprising a plurality of amplifier stages connected in cascade and each having a fixed low-gain characteristic, means for limiting the maximum output of each of said plurality of amplifier stages to a given value, means including a multiplexer for taking an output from each of said cascaded amplifier stages, means including a control circuit for said multiplexer to cause said multiplexer to select for said amplified output signal the output of different ones of said plurality of amplifier stages at different times in response to amplitude variations in the output of said plurality of amplifier stages, and means for adding the outputs of selected ones of said plurality of amplifier stages together to produce a combined control signal and means for coupling said control signal to said control circuit.

Claim 10

Apparatus for amplifying an electrical input signal to provide an amplified electrical output signal comprising a plurality of amplifier stages connected in cascade and each having a fixed low-gain characteristic, means for limiting the maximum output of each of said plurality of amplifier stages to a given value, means including a multiplexer for taking an output from each of said cascaded amplifier stages, means including a control circuit for said multiplexer to cause said multiplexer to select for said amplified output signal the output of different ones of said plurality of amplifier stages at different times in response to amplitude variations in the output of said plurality of amplifier stages, and means for adding the outputs of selected ones of said plurality of amplifier stages together to produce a combined control signal and means for coupling said control signal to said control circuit.

Claim 11

Apparatus according to claim 8 including means coupling the output of the first of said plurality of stages of amplification and the outputs of each subsequent odd numbered one of said plurality of stages of amplification together to produce a first combined signal, means coupling the output of the second of said plurality of stages of amplification and the outputs of each subsequent even numbered ones of said plurality of stages of amplification together to produce a second combined signal, means coupling said first combined signal to said second combined signal which means shifts the phase of said first combined signal by 180*, whereby said first combined signal and said second combined signal are combined to produce a control signal, and means for coupling said control signal to said control circuit.

Claim 12

Apparatus of claim 9 including a display device and means coupling said control signal to said display device.

Claim 13

Apparatus of claim 10 wherein said means coupling said control signal to said control circuit includes means providing full wave rectification of said control signal.

Claim 14

Apparatus according to claim 8 wherein narrow band filter means are interposed between the first and second ones of said plurality of amplifier stages.

Claim 15

Apparatus according to claim 8 wherein a buffer amplifier having unity characteristic gain is interposed between the output of the first of said stages of amplification and said multiplexer.

Claim 16

Apparatus according to claim 8 wherein each of said plurality of stages of amplification comprises a solid-state operational amplifier connected to operate in their inverting mode of amplification.

Claim 17

Apparatus according to claim 14 wherein the second and each subsequent one of said plurality of stages of amplification provides a gain of 12 db.

Claim 18

Apparatus according to claim 15 wherein the first of said plurality of stages of amplification provides a gain of 24 db.

Claim 19

Apparatus according to claim 8 wherein said means for limiting the maximum output of each of said amplification stages includes a network comprising a pair of Zener diodes connected in series across a power supply, a pair of conventional diodes connected in series with each other and in parallel with said series connected Zener diodes, the output of an amplification stage being connected to the junction of said series connected Zener diodes, and a resistance means connected between the junction of said conventional diodes and ground.

Claim 20

Apparatus according to claim 17 wherein a pair of conventional diodes are connected with reversed polarity in parallel with each other between the common connection of said series connected conventional diodes and the input terminal of the associated amplification stage.

Claim 21

Apparatus for amplifying seismic signals comprising: a plurality of amplifier stages connected in cascade, each stage having a fixed gain characteristic, with means for applying seismic signals to the first of such stages, means connected to receive continuously the outputs of a plurality of said amplifier stages and operative to add said outputs to produce a control signal in response to the magnitude of a summed combination of the outputs of such stages, means for selecting the output of only one of said cascaded amplifier stages as an output for the apparatus in response to said control signal whereby the output of different ones of the amplifier stages is used at different times according to amplitude variations in the seismic signals.

Claim 22

Apparatus for amplifying seismic signals comprising: a plurality of amplifier stages connected in cascade, each stage having a fixed gain characteristic, with means for applying seismic signals to the first of such stages, means connected to receive continuously the outputs of a plurality of said amplifier stages and operative to add said outputs to produce a control signal in response to the magnitude of a summed combination of the outputs of such stages, means for selecting the output of only one of said cascaded amplifier stages as an output for the apparatus in response to said control signal whereby the output of different ones of the amplifier stages is used at different times according to amplitude variations in the seismic signals.