Communication system with adaptive receiver

Claim 2

In a transmission system comprising a radio transmitter and receiver, wherein said transmitter includes means for producing binary pulse signals of baud duration and means for producing phase modulated radio waves in response to said signals, a receiver including radio wave receiving means, a pair of demodulators connected to said receiving means, a variable frequency oscillator having two phase displaced outputs connected to the demodulators, respectively, a delay means having a delay substantially equal to the period of said binary signals, a multiplier circuit connected to the output of one of said demodulators, said delay means being connected between the other demodulator and the multiplier circuit, an automatic frequency control circuit connected from the output of said multiplier circuit to said oscillator, and means connected to the output of the delay means and said other demodulator for deriving the transmitted signals.

Claim 3

A system according to claim 1, wherein said automatic frequency control circuit includes integrating means connected to the output of said means for deriving, switching means for reversing the polarity of the output of the integrating means in response to a signal of said one value, and a smoothing circuit connecting said switching means to said oscillator.

Claim 4

A system according to claim 2, including means for resetting said integrating means to a reference voltage value at the end of each baud interval.

Claim 5

A system according to claim 1, wherein said last mentioned means includes a second multiplier connected to the output of said delay means and said other demodulator, an integrating circuit having a pair of inputs one of which is connected to the output of said second multiplier, additional delay means for supplying the output of the multiplier with a delay equal to the baud duration and with a reversal of polarity to the other of said pair of inputs of the integrating circuit, means for sampling the output of said integrating means at the end of each baud interval, and means for detecting the voltage polarity of the sampled outputs to indicated the values of the binary transmitted signals.

Claim 6

A transmission system comprising a radio transmitter and receiver, said transmitter including means for producing and transmitting a carrier wave modulated by binary signals, said receiver including means for receiving said carrier wave, a pair of demodulators connected to said receiving means, a tunable oscillator having two outputs connected to the demodulators, respectively, in phase quadrature relation, delay means having a delay substantially equal to the period of the binary signals, a multiplier circuit connected to the output of one of said demodulators, said delay means being connected between the other demodulator and the multiplier circuit, an automatic frequency control circuit connected from the output of said multiplier circuit to said oscillator, and means connected to the output of the delay means and said other demodulator for deriving the transmitted signals.

Claim 7

A transmission system comprising a radio transmitter and receiver, said transmitter including means for producing and transmitting a carrier wave modulated by binary signals, said receiver including means for receiving said carrier wave, a pair of demodulators connected to said receiving means, a tunable oscillator having two outputs connected to the demodulators, respectively, in phase quadrature relation, delay means having a delay substantially equal to the period of the binary signals, a multiplier circuit connected to the output of one of said demodulators, said delay means being connected between the other demodulator and the multiplier circuit, an automatic frequency control circuit connected from the output of said multiplier circuit to said oscillator, and means connected to the output of the delay means and said other demodulator for deriving the transmitted signals.

Claim 8

A transmission system comprising a radio transmitter and receiver, said transmitter including a generator producing positive and negative pulses, a modulator including a source of radio carrier waves, keying means for selectively connecting the pulse generator to the modulator so as to change the polarity of the pulses supplied thereto in response to a keying signal having one given value, said receiver including radio wave receiving means, a pair of linear demodulators connected to said receiving means, a tunable oscillator having two outputs in phase quadrature connected to the demodulators, respectively, a delay means having a delay substantially equal to the pulse period of the pulse generator, a multiplier circuit connected to the output of one of said demodulators, said delay means being connected between the other demodulator and the multiplier circuit, an automatic frequency control circuit connected from the output of said multiplier circuit to said oscillator, and means connected to the output of the delay means and said other demodulator for deriving the transmitted signals.

Claim 9

A transmission system comprising a radio transmitter and receiver, said transmitter including a generator producing positive and negative pulses, a modulator including a source of radio carrier waves, keying means for selectively connecting the pulse generator to the modulator so as to change the polarity of the pulses supplied thereto in response to a keying signal having one given value, said receiver including radio wave receiving means, a pair of linear demodulators connected to said receiving means, a tunable oscillator having two outputs in phase quadrature connected to the demodulators, respectively, a delay means having a delay substantially equal to the pulse period of the pulse generator, a multiplier circuit connected to the output of one of said demodulators, said delay means being connected between the other demodulator and the multiplier circuit, an automatic frequency control circuit connected from the output of said multiplier circuit to said oscillator, and means connected to the output of the delay means and said other demodulator for deriving the transmitted signals.

Claim 10

A system according to claim 6, wherein said automatic frequency control circuit includes integrating means connected to the output of the multiplier circuit, switching means for reversing the polarity of the output of the integrating means in response to a signal of said one value, and a smoothing circuit connecting said switching means to said oscillator.

Claim 11

A system according to claim 7, including means for resetting said integrating means to a reference voltage value at the end of each baud interval.

Claim 12

A system according to claim 8, wherein said means for deriving the transmitted signals includes a second multiplier connected to said delay means and said other demodulator, a second integrating circuit having a pair of inputs one of which is connected to the output of said second multiplier, delay means for supplying the output of the second multiplier with a delay equal to the baud duration and with a reversal of polarity to the other of said pair of inputs of the second integrating circuit, means for sampling the output of said second integrating means at the end of each interval, and means for detecting the voltage polarity of the sampled outputs to indicate the values of the binary transmitted signals.

Claim 13

A transmission system comprising a radio transmitter and receiver, said transmitter including a generator producing positive and negative pulses, suppressed carrier wave modulating means, a source of radio carrier waves connected to said modulator, mark and space keying means for selectively connecting the pulse generator to the modulator so as to change the polarity of said pulses supplied thereto in response to a mark signal, said receiver including radio wave receiving means, a pair of demodulators connected in parallel to said receiving means, a tunable oscillator having two outputs connected in phase quadrature to the demodulators, means for multiplying each pulse signal from the output of one demodulator by the immediately preceding pulse signal from the output of the other demodulator, an automatic frequency control circuit connected from the output of said multiplying means to said oscillator, and means connected to the output of one of said demodulators for multiplying each pulse signal by the immediately preceding signal and determining the transmitted signals.

Claim 14

A transmission system comprising a radio transmitter and receiver, said transmitter including a generator producing positive and negative pulses, suppressed carrier wave modulating means, a source of radio carrier waves connected to said modulator, mark and space keying means for selectively connecting the pulse generator to the modulator so as to change the polarity of said pulses supplied thereto in response to a mark signal, said receiver including radio wave receiving means, a pair of demodulators connected in parallel to said receiving means, a tunable oscillator having two outputs connected in phase quadrature to the demodulators, means for multiplying each pulse signal from the output of one demodulator by the immediately preceding pulse signal from the output of the other demodulator, an automatic frequency control circuit connected from the output of said multiplying means to said oscillator, and means connected to the output of one of said demodulators for multiplying each pulse signal by the immediately preceding signal and determining the transmitted signals.

Claim 15

A communication system comprising a transmitter and receiver, said transmitter including a pulse generator, encoding means including selectively operable multiposition switching means for generating any one of a mutually orthogonal set of sequences of two-valued pulses, each position of the switching means representing a signal to be transmitted, a clock, generator connected to said pulse generator and encoding means for synchronizing the same, a suppressed carrier wave modulator, means for supplying the pulses from said pulse generator to said modulator and responsive to the two-valued pulses for changing the modulation of the carrier wave from one fixed value to another whenever said last mentioned pulses have a given one of their two values, and means for transmitting the modulated carrier wave; said receiver comprising means for receiving the transmitted waves, two demodulators connected to the receiving means, a tunable oscillator having connections to the demodulators for supplying thereto, respectively, carrier frequency waves in phase quadrature, delay means having a delay equal to the period of the clock generator, said delay means being connected to the output of one of said demodulators, a combining circuit connected to the output of the delay means and the other demodulator, an automatic frequency control circuit connected between the output of the combining circuit and the oscillator for tuning the latter to the frequency of the received carrier wave, and detecting means connected to the outputs of the delay means and one of said demodulators for deriving the transmitted signals.

Claim 16

A communication system comprising a transmitter and receiver, said transmitter including a pulse generator, encoding means including selectively operable multiposition switching means for generating any one of a mutually orthogonal set of sequences of two-valued pulses, each position of the switching means representing a signal to be transmitted, a clock, generator connected to said pulse generator and encoding means for synchronizing the same, a suppressed carrier wave modulator, means for supplying the pulses from said pulse generator to said modulator and responsive to the two-valued pulses for changing the modulation of the carrier wave from one fixed value to another whenever said last mentioned pulses have a given one of their two values, and means for transmitting the modulated carrier wave; said receiver comprising means for receiving the transmitted waves, two demodulators connected to the receiving means, a tunable oscillator having connections to the demodulators for supplying thereto, respectively, carrier frequency waves in phase quadrature, delay means having a delay equal to the period of the clock generator, said delay means being connected to the output of one of said demodulators, a combining circuit connected to the output of the delay means and the other demodulator, an automatic frequency control circuit connected between the output of the combining circuit and the oscillator for tuning the latter to the frequency of the received carrier wave, and detecting means connected to the outputs of the delay means and one of said demodulators for deriving the transmitted signals.

Claim 17

A system according to claim 11, wherein said receiver includes decoding means for generating an orthogonal set of said sequences of pulses, and said detecting means and said automatic frequency control circuit each including a plurality of channels, each channel including a multiplier circuit, and means for supplying one of said sequences of pulses from said decoding means to each of said last circuits, an integrating circuit connected to the output of each multiplier circuit, switching means for sampling the output of each integrator in the channels of the detecting means at the end of each signal, and switching means for selectively connecting only one of the automatic frequency control channels to the oscillator at the end of each received signal in response to the particular sequence of pulses received.

Claim 18

A digital information transmitter comprising a pulse generator, encoding means including selectively operable multiposition switching means for generating any one of a mutually orthogonal set of sequences of two-valued pulses, each position of the switching means representing a signal to be transmitted, a clock generator connected to said pulse generator and encOding means for synchronizing the same, a suppressed carrier wave modulator, means for supplying the pulses from said pulse generator to said modulator and responsive to the two-valued pulses for changing the modulation of the carrier wave from one fixed value to another whenever said last mentioned pulses have a given one of their two values and means for transmitting the modulated carrier wave.

Claim 19

A digital information transmitter comprising a pulse generator, encoding means including selectively operable multiposition switching means for generating any one of a mutually orthogonal set of sequences of two-valued pulses, each position of the switching means representing a signal to be transmitted, a clock generator connected to said pulse generator and encOding means for synchronizing the same, a suppressed carrier wave modulator, means for supplying the pulses from said pulse generator to said modulator and responsive to the two-valued pulses for changing the modulation of the carrier wave from one fixed value to another whenever said last mentioned pulses have a given one of their two values and means for transmitting the modulated carrier wave.