US4398062A — Apparatus for privacy transmission in system havi…

Claim 1

Independent Claim 260 words

Apparatus for communicating an analog signal over a bandwidth constrained channel comprising: transmitter means including sampling means for sampling said analog signal at a first rate so as to provide periodic samples of said analog signal occurring at first repetition rate, multiplexer means responsive to said samples of said analog signal for deriving first and second pulse amplitude modulated signals therefrom each bearing the information contained in alternate samples of said analog signal, and quadrature modulator means responsive to said first and second pulse amplitude modulated signals for respectively modulating first and second orthogonal carrier signals in accordance therewith and for combining and transmitting said modulated orthogonal signals over said bandwidth constrained channel; and, receiver means including quadrature demodulator means for receiving said modulated orthogonal signals which have been transmitted over said channel and for recovering said first and second pulse amplitude modulated signals therefrom, sampling means responsive to said first and second pulse samplitude modulated signals for alternately sampling said signals at a rate which is greater than said first repetition rate, and filtering means for adaptively weighting and combining said samples to provide a filtered output signal corresonding to said analog signal, said filtering means including means for storing a plurality of consecutive said samples, coefficient circuitry for multiplying each of said stored samples by a respective coefficient to provide a plurality of weighted signals, output means responsive to said weighted samples for deriving said filtered analog signal therefrom, and automatic coefficient adjustment circuitry for automatically adjusting said coefficients so as to thereby automatically adapt said filtering means.

Claim 2

Dependent Claim 260 words

Apparatus for communicating an analog signal over a bandwidth constrained channel comprising: transmitter means including sampling means for sampling said analog signal at a first rate so as to provide periodic samples of said analog signal occurring at first repetition rate, multiplexer means responsive to said samples of said analog signal for deriving first and second pulse amplitude modulated signals therefrom each bearing the information contained in alternate samples of said analog signal, and quadrature modulator means responsive to said first and second pulse amplitude modulated signals for respectively modulating first and second orthogonal carrier signals in accordance therewith and for combining and transmitting said modulated orthogonal signals over said bandwidth constrained channel; and, receiver means including quadrature demodulator means for receiving said modulated orthogonal signals which have been transmitted over said channel and for recovering said first and second pulse amplitude modulated signals therefrom, sampling means responsive to said first and second pulse samplitude modulated signals for alternately sampling said signals at a rate which is greater than said first repetition rate, and filtering means for adaptively weighting and combining said samples to provide a filtered output signal corresonding to said analog signal, said filtering means including means for storing a plurality of consecutive said samples, coefficient circuitry for multiplying each of said stored samples by a respective coefficient to provide a plurality of weighted signals, output means responsive to said weighted samples for deriving said filtered analog signal therefrom, and automatic coefficient adjustment circuitry for automatically adjusting said coefficients so as to thereby automatically adapt said filtering means.

Claim 3

Dependent Claim 83 words

Apparatus as set forth in claim 1 and further comprising means for training said adaptive filter including first means associated with said transmitter means for providing a statistically random, multilevel first signal having a determinable information content to said multiplexer means, second means associated with said receiver means for reproducing said first signal, means for comparing said filtered output signal with said reproduced first signal, and means for adjusting the weights in said adaptive filter in dependence upon the results of said comparison.

Claim 4

Dependent Claim 72 words

Apparatus as set forth in claim 2, wherein said first means and said second means each includes a like pseudorandom number generator for providing said first signal, and wherein means are provided for synchronizing the operation of said pseudorandom number generators so that said generators produce the same pseudorandom numbers, said synchronizing means including means for loading the pseudorandom number contained in one of said generators into the other of said generators.

Claim 5

Dependent Claim 71 words

Apparatus as set forth in claim 3, wherein said synchronizing means includes means for transmitting said pseudorandom number to be loaded into the other of said generators over said channel one digit at a time as a bilevel signal such that a positive full scale signal transmitted over said channel signifies one binary data state and a negative full scale signal transmitted over said channel signifies the other binary data state.

Claim 6

Dependent Claim 196 words

In a QAM receiver of the type adapted to receive bursts of signals having a bandwidth B Hz and sent at a predetermined rate of 1/T signals per second over a channel, wherein the receiver includes an automatic adaptive equalizer having taps spaced equally apart, tap coefficient circuitry for multiplying the output of each tap by a respective tap coefficient, and adjustment circuitry for adjusting said tap coefficients, output circuitry responsive to said equalizer for providing output signals at times kT+t, k=0, 1, . . . , where t is a timing epoch, and detection circuitry for detecting the presence of an incoming burst of signals at a predetermined position in said receiver, that improvement wherein said taps are spaced apart by T/n seconds, where n is greater than TB, and control circuitry is provided for early actuation of said adjustment circuitry at a predetermined time dependent upon the time of said detection, to begin adjustment of said tap coefficients and hence training of said equalizer regardless of the initial value of said timing epoch, whereby the data capacity of said receiver is increased by reduction of the time required for set up of said receiver.

Claim 7

Dependent Claim 196 words

In a QAM receiver of the type adapted to receive bursts of signals having a bandwidth B Hz and sent at a predetermined rate of 1/T signals per second over a channel, wherein the receiver includes an automatic adaptive equalizer having taps spaced equally apart, tap coefficient circuitry for multiplying the output of each tap by a respective tap coefficient, and adjustment circuitry for adjusting said tap coefficients, output circuitry responsive to said equalizer for providing output signals at times kT+t, k=0, 1, . . . , where t is a timing epoch, and detection circuitry for detecting the presence of an incoming burst of signals at a predetermined position in said receiver, that improvement wherein said taps are spaced apart by T/n seconds, where n is greater than TB, and control circuitry is provided for early actuation of said adjustment circuitry at a predetermined time dependent upon the time of said detection, to begin adjustment of said tap coefficients and hence training of said equalizer regardless of the initial value of said timing epoch, whereby the data capacity of said receiver is increased by reduction of the time required for set up of said receiver.

Claim 8

Dependent Claim 43 words

The improvement of claim 5 wherein said detection circuitry comprises means for detecting the arrival of an incoming burst of signals at said receiver, and said control circuitry comprises means for actuating said adjustment circuitry within a predetermined time interval after such detection.

Claim 9

Dependent Claim 20 words

The improvement of claim 5 wherein said predetermined time interval is less than the total delay length of said equalizer.

Claim 10

Dependent Claim 13 words

The improvement of claim 5 wherein n is an integer greater than 1.

Claim 11

Dependent Claim 7 words

The improvement of claim 8 wherein n=2.

Claim 12

Dependent Claim 30 words

The improvement of claim 5 wherein said receiver includes sampling circuitry for sampling received signals at a rate of n/T samples per second and providing said samples to said equalizer.

Claim 13

Dependent Claim 50 words

The improvement of claim 5 wherein said control circuitry comprises means for actuating said adjustment circuitry to begin training of said equalizer when the first signal in said burst has arrived at a pre-selected tap position in said equalizer at which it is desired to locate the principal tap coefficient.

Claim 14

Dependent Claim 35 words

The improvement of claim 5 wherein said receiver includes timing recovery circuitry comprising means for establishing and keeping the principal said tap coefficient within a predetermined number of taps from the center of said equalizer.

Claim 15

Dependent Claim 32 words

The improvement of claim 5 wherein said receiver is part of a central station in a multi-point transmission system having in addition a central transmitter and at least one remote transmitter/receiver station.

Claim 16

Dependent Claim 56 words

The improvement of claim 13 wherein each of said at least one remote transmitter is adapted to send a training sequence as a preamble of each said burst, and said control circuitry of said central receiver comprises means to actuate said adjustment circuitry to begin training of said equalizer with the first signals in said preamble.

Claim 17

Dependent Claim 26 words

The improvement of claim 5 wherein said receiver includes timing recovery circuitry for adjusting t, and said control circuitry comprises means for actuating said adjustment circuitry.

Claim 18

Dependent Claim 128 words

In a receiver having an adaptive equalizer to which received signals are applied for filtering received signals having information originally provided in discrete symbol intervals occurring at a first rate, said adaptive equalizer including means for sampling said received signals and means for weighting and combining the resulting samples to provide filtered signals and means for adjusting the weights of said samples, the improvement wherein; said sampling means samples said received signals at a rate greater than said first rate, and said adjusting means includes means for beginning said adjusting of said weights, and thus training of said equalizer, within a predetermined time after receipt of said received signals and regardless of the initial timing relationship between said sampling of said received signals and said discrete symbol intervals.

Claim 19

Dependent Claim 128 words

In a receiver having an adaptive equalizer to which received signals are applied for filtering received signals having information originally provided in discrete symbol intervals occurring at a first rate, said adaptive equalizer including means for sampling said received signals and means for weighting and combining the resulting samples to provide filtered signals and means for adjusting the weights of said samples, the improvement wherein; said sampling means samples said received signals at a rate greater than said first rate, and said adjusting means includes means for beginning said adjusting of said weights, and thus training of said equalizer, within a predetermined time after receipt of said received signals and regardless of the initial timing relationship between said sampling of said received signals and said discrete symbol intervals.

Claim 20

Dependent Claim 19 words

In a receiver as set forth in claim 16 including means for detecting the arrival of said received signals.

Claim 21

Dependent Claim 29 words

In a receiver as set forth in claim 17 including means for beginning the adjusting of said weights withhin a predetermined time interval after said detection of said arrival.

Claim 22

Dependent Claim 30 words

In a receiver as set forth in claim 16 wherein said sampling means samples said received signals at a second rate and which is a multiple of said first rate.

Claim 23

Dependent Claim 21 words

In a receiver as set forth in claim 19 wherein said second rate is an even mutiple of said first rate.

Claim 24

Dependent Claim 20 words

In a receiver as set forth in claim 19 wherein said second rate is twice that of said first rate.

Claim 25

Dependent Claim 41 words

In a receiver as set forth in claim 16 wherein said adaptive equalizer includes means for storing a plurality of consecutive said samples and means for beginning the adjusting of said weights once a predetermined number of samples has been stored.

Claim 26

Dependent Claim 149 words

In a communications system having a transmitter and a receiver adapted to provide communications over a communications channel, comprising said transmitter includes means for transmitting an information bearing signal in discrete symbol intervals occurring at a first rate; and said receiver includes an adaptive equalizer to which received signals are applied for filtering thereof with said adaptive filter including means for samplng said received signals and means for weighting and combining the resulting samples to provide filtered signals and means for adjusting the weights of said samples, said sampling means sampling said received signals at a greater than said first rate and said adjusting means includes means for beginning said adjusting of said weights and thus training of said equalizer within a predetermined time after receipt of said received signals and regardless of the initial timing relationship between said sampling of said received signals and said discrete symbol intervals.

Claim 27

Dependent Claim 149 words

In a communications system having a transmitter and a receiver adapted to provide communications over a communications channel, comprising said transmitter includes means for transmitting an information bearing signal in discrete symbol intervals occurring at a first rate; and said receiver includes an adaptive equalizer to which received signals are applied for filtering thereof with said adaptive filter including means for samplng said received signals and means for weighting and combining the resulting samples to provide filtered signals and means for adjusting the weights of said samples, said sampling means sampling said received signals at a greater than said first rate and said adjusting means includes means for beginning said adjusting of said weights and thus training of said equalizer within a predetermined time after receipt of said received signals and regardless of the initial timing relationship between said sampling of said received signals and said discrete symbol intervals.

Claim 28

Dependent Claim 57 words

In a communications system as set forth in claim 23, wherein said transmitter includes means for sampling a said information bearing signal at said first rate and multiplexer means responsive to said sampled information signal for providing first and second pulse amplitude modulated signals therefrom, each bearing the information contained in alternate samples of said information signal.

Claim 29

Dependent Claim 52 words

In a communications system as set forth in claim 24 wherein said transmitter further includes quadrature modulator means responsive to said first and second pulse amplitute modulated signals for respectively modulating first and second orthogonal carrier signals in accordance therewith and for combining and transmitting said modulated signals over said communications channel.

Claim 30

Dependent Claim 34 words

In a communications system as set forth in claim 25 wherein said receiver further includes quadrature demodulator means for receiving said modulated orthogonal signals for recovering said first and second pulse amplitude signals therefrom.

Claim 31

Dependent Claim 28 words

In a communications system as set forth in claim 26 wherein said sampling means alternately samples said first and second pulse amplitude modulated signals at said greater rate.

Claim 32

Dependent Claim 22 words

In a communications system as set forth in claim 27 wherein said greater rate is an even multiple of said first rate.

Claim 33

Dependent Claim 40 words

In a communication system as set forth in claim 28 including means for detecting the arrival of said orthogonal signals and means for beginning the adjusting of said weights within a predetermined time interval after said detection of said arrival.

Claim 34

Independent Claim 105 words

A method of filtering a received signal including symbols transmitted in discrete time intervals occurring at a first rate comprising sampling said received signal and weighting and combining the resulting samples to thus provide a filtered signal and adjusting the weights of the samples, the improvement wherein; the step of sampling said received signal includes the step of sampling at a rate greater than said first rate and said weighting step includes the step of beginning adjustment of said weighting within a predetermined time after the arrival of said received signal regardless of the initial timing relationship between said sampling and said discrete time intervals.

Claim 35

Independent Claim 105 words

A method of filtering a received signal including symbols transmitted in discrete time intervals occurring at a first rate comprising sampling said received signal and weighting and combining the resulting samples to thus provide a filtered signal and adjusting the weights of the samples, the improvement wherein; the step of sampling said received signal includes the step of sampling at a rate greater than said first rate and said weighting step includes the step of beginning adjustment of said weighting within a predetermined time after the arrival of said received signal regardless of the initial timing relationship between said sampling and said discrete time intervals.

Claim 36

Dependent Claim 23 words

A method as set forth in claim 30 wherein said weighting step includes the step of detecting the arrival of said received signal.

Claim 37

Dependent Claim 36 words

A method as set forth in claim 31 wherein said weighting step further includes the step of beginning the adjusting of said weighting within a predetermined time interval after detecting the arrival of said received signal.

Claim 38

Dependent Claim 32 words

A method as set forth in claim 32 wherein said sampling step includes the step of sampling said received signal at a rate which is an even multiple of said first rate.

Claim 39

Dependent Claim 27 words

A method as set forth in claim 32 wherein said sampling of said received signal is at a rate which is twice that of said first rate.

Claim 40

Dependent Claim 103 words

An adaptive equalizer for processing a received signal having information provided in discrete intervals occurring at a first rate, the adaptive equalizer comprising: sampling means for producing a resulting sampled signal by sampling the received signal at a second rate greater than said first rate; means for weighting and combining samples from said resulting sampled signal in order to provide filtered output signals; and means for adjusting said means for weighting and combining within a predetermined time after receipt of the received signals and independent of the initial timing relationship between the discrete intervals of the received signal and said resulting sampled signal.

Claim 41

Dependent Claim 103 words

An adaptive equalizer for processing a received signal having information provided in discrete intervals occurring at a first rate, the adaptive equalizer comprising: sampling means for producing a resulting sampled signal by sampling the received signal at a second rate greater than said first rate; means for weighting and combining samples from said resulting sampled signal in order to provide filtered output signals; and means for adjusting said means for weighting and combining within a predetermined time after receipt of the received signals and independent of the initial timing relationship between the discrete intervals of the received signal and said resulting sampled signal.

Claim 42

Dependent Claim 20 words

An adaptive equalizer as set forth in claim 35 wherein said second rate is a multiple of said first rate.

Claim 43

Dependent Claim 21 words

An adaptive equalizer as set forth in claim 36 wherein said second rate is an even multiple of said first rate.

Claim 44

Dependent Claim 42 words

An adaptive equalizer as set forth in claim 35 including means for storing a plurality of consecutive said sampled signals and means for beginning said adjusting of said means for weighting once a predetermined number of said sampled signals have been stored.

Claim 45

Independent Claim 95 words

A method for processing a received signal having information provided in discrete intervals occurring at a first rate, comprising the steps of: sampling the received signal at a second rate greater than said first rate in order to produce a resulting sampled signal; weighting and combining samples from said resulting sampled signal in order to provide filtered output signals; and beginning adjustment of said weighting within a predetermined time after receipt of the received signal and independent of the initial timing relationship between the discrete intervals of the received signal and said resulting sampled signal.

Claim 46

Independent Claim 95 words

A method for processing a received signal having information provided in discrete intervals occurring at a first rate, comprising the steps of: sampling the received signal at a second rate greater than said first rate in order to produce a resulting sampled signal; weighting and combining samples from said resulting sampled signal in order to provide filtered output signals; and beginning adjustment of said weighting within a predetermined time after receipt of the received signal and independent of the initial timing relationship between the discrete intervals of the received signal and said resulting sampled signal.

Claim 47

Dependent Claim 36 words

A method as set forth in claim 39 including the steps of storing a plurality of consecutive said samples and beginning said adjustment of said weighting once a predetermined number of said samples have been stored.

Claim 48

Dependent Claim 20 words

A method as set forth in claim 39 wherein said second rate is an even multiple of said first rate.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1986-08-08	1987-02-07	1987-08-09	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1990-08-08	1991-02-07	1991-08-09	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1994-08-08	1995-02-07	1995-08-09	$7700.00	Window Closed / Lapsed

Apparatus for privacy transmission in system having bandwidth constraint

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag