Multicorrelator for analogue signals employing pulse width-amplitude multiplication and operating in real time

Claim 2

A multicorrelator determining the correlation function between a first and a second randomly variable physical magnitude, for a plurality of n points, comprising: A first general input terminal for a first variable voltage, the variable amplitude of which represents said first magnitude; a second general input terminal for a second variable voltage, the variable amplitude of which represents said second magnitude; sampling and modulating means having a signal input terminal connected to said first general input terminal, for receiving said first variable voltage therefrom, and an output terminal, said means deducing, from said first variable voltage applied to its input terminal, a succession of pulses which are width modulated by the variable amplitude of said first voltage, said succession of pulses being delivered on said output terminal; a shifting register having (n-1) stages and including an input terminal connected to said output terminal of said sampling and modulating means, for receiving said succession of width modulated pulses therefrom, and (n-1) output terminals, one for each stage thereof, said (n-1) stages imparting to each the same time delay to said pulses so that the (n-1) output terminals of the successive stages deliver successions of pulses with delays equal to said delay, twice said time delay, three times said time delay, ..... (n-1) times said time delay respectively; n pulse width-amplitude multipliers, having each a first input terminal connected to said second general input terminal, for receiving said second variable voltage therefrom, and a second input terminal connected to a different one of the following output terminals: the output terminal of said sampling and modulating means and the (n-1) output terminals of said shifting register, each of said multipliers delivering a succession of alternate even and odd pulses having an amplitude proportional to the amplitude of the second variable voltage received on the first input thereof, the odd pulses having the polarity of said second variable voltage and the duration of the width modulated pulses arriving on said second input thereof, whereas the even pulses have a polarity opposed to the polarity of said second variable voltage and the duration of the intervals between the width modulated pulses arriving on said second input thereof; and n low-pass filters having each one an input terminal connected with a said output terminal of a different one among said n multipliers, for receiving one of said successions of alternate pulses therefrom, and an output terminal delivering each the correlation function for a different one of said n points.

Claim 3

A multicorrelator determining the correlation function between a first and a second randomly variable physical magnitude; for a plurality of n points, comprising: a first general input terminal for a first variable voltage, the variable amplitude of which represents said first magnitude; a second general input terminal for a second variable voltage, the variable amplitude of which represents said second magnitude; sampling and modulating means having a signal input terminal connected to said first general input terminal, for receiving said first variable voltage therefrom, and an output terminal, said means deducing, from said first variable voltage applied to its input terminal, a succession of pulses which are width modulated by the variable amplitude of said first voltage, said succession of pulses being delivered on said output terminal; a shifting register having (n-1) stages and including an input terminal connected to said output terminal of said sampling and modulating means, for receiving said succession of width modulated pulses therefrom, and (n-1) output terminals, one for each stage thereof, said (n-1) stages imparting to each the same time delay to said pulses so that the (n-1) output terminals of the successive stages deliver successions of pulses with delays equal to said time delay, twice said time delay, three times said time delay, ..... (n-1) times said time delay respectively; a reversing unit with an input terminal connected to said second general input terminal, for receiving the second variable voltage therefrom and an output terminal delivering a third variable voltage which has the same amplitude as said second variable voltage, but an opposite polarity; n switches having a first signal input terminal connected to said first general input terminal, for receiving said second variable voltage therefrom, a second signal input terminal connected to said output terminal of said reversing unit, for receiving said third variable voltage therefrom, a control input terminal connected to the output terminal of said sampling and modulation means, for receiving said succession of alternate pulses therefrom, and an output terminal, each of said switches connecting said output terminal thereof to said first signal input terminal thereof, in response to a pulse in said succession applied on the control input terminal thereof, but to said second signal input terminal in the absence of a pulse in said succession applied on the control input terminal thereof, each of said switches delivering a succession of alternate even and odd pulses having an amplitude proportional to the amplitude of the second variable voltage received on the first input thereof, the odd pulses having the polarity of said second variable voltage and the duration of the width modulated pulses arriving on said second input thereof, whereas the even pulses have a polarity opposed to the polarity of said second variable voltage and the duration of the intervals between the width modulated pulses arriving on said second input thereof; and n low-pass filters having each one an input terminal connected with a said output terminal of a different one among said n multipliers, for receiving one of said successions of alternate pulses therefrom; and an output terminal delivering each the correlation function for a different one of said n points.

Claim 4

A multicorrelator determining the correlation function between a first and a second randomly variable physical magnitude; for a plurality of n points, comprising: a first general input terminal for a first variable voltage, the variable amplitude of which represents said first magnitude; a second general input terminal for a second variable voltage, the variable amplitude of which represents said second magnitude; sampling and modulating means having a signal input terminal connected to said first general input terminal, for receiving said first variable voltage therefrom, and an output terminal, said means deducing, from said first variable voltage applied to its input terminal, a succession of pulses which are width modulated by the variable amplitude of said first voltage, said succession of pulses being delivered on said output terminal; a shifting register having (n-1) stages and including an input terminal connected to said output terminal of said sampling and modulating means, for receiving said succession of width modulated pulses therefrom, and (n-1) output terminals, one for each stage thereof, said (n-1) stages imparting to each the same time delay to said pulses so that the (n-1) output terminals of the successive stages deliver successions of pulses with delays equal to said time delay, twice said time delay, three times said time delay, ..... (n-1) times said time delay respectively; a reversing unit with an input terminal connected to said second general input terminal, for receiving the second variable voltage therefrom and an output terminal delivering a third variable voltage which has the same amplitude as said second variable voltage, but an opposite polarity; n switches having a first signal input terminal connected to said first general input terminal, for receiving said second variable voltage therefrom, a second signal input terminal connected to said output terminal of said reversing unit, for receiving said third variable voltage therefrom, a control input terminal connected to the output terminal of said sampling and modulation means, for receiving said succession of alternate pulses therefrom, and an output terminal, each of said switches connecting said output terminal thereof to said first signal input terminal thereof, in response to a pulse in said succession applied on the control input terminal thereof, but to said second signal input terminal in the absence of a pulse in said succession applied on the control input terminal thereof, each of said switches delivering a succession of alternate even and odd pulses having an amplitude proportional to the amplitude of the second variable voltage received on the first input thereof, the odd pulses having the polarity of said second variable voltage and the duration of the width modulated pulses arriving on said second input thereof, whereas the even pulses have a polarity opposed to the polarity of said second variable voltage and the duration of the intervals between the width modulated pulses arriving on said second input thereof; and n low-pass filters having each one an input terminal connected with a said output terminal of a different one among said n multipliers, for receiving one of said successions of alternate pulses therefrom; and an output terminal delivering each the correlation function for a different one of said n points.

Claim 5

A multicorrelator according to claim 2, further comprising display means with an input terminal, and a switching device having n input terminals, each connected to the output terminal of a different one among said low-pass filters, and one output terminal connected with the input terminal of said display means, said switching device connecting successively and cyclically each of its input terminals to its output terminal.

Claim 6

A multicorrelator according to claim 2, wherein the width of pulses in the succession of pulses delivered by said sampling and modulating means, as well as by said shifting register, is an integral multiple of the reciprocal of the transfer frequency of said shifting register.

Claim 7

A multicorrelator according to claim 2, wherein said shifting register cooperates with a clock delivering on its output terminal regularly spaced clock pulses and with an inverter having an input terminal connected to said output of said sampling and moduLating means, for receiving said succession of pulses, and an output terminal delivering a succession of pulses of same amplitude and duration but of opposite polarity as compared with the received succession of pulses, and wherein each of said (n-1) stages of said shifting register comprises a bistable circuit, including two input terminals and two output terminals, and two gates, each of said gates including two input terminals, and one output terminal, one input terminal of each of said gates being connected with said output terminal of said clock, to receive said clock pulses therefrom, the other input terminal of each of said gates, with the exception of the gates belonging to the first stage, being connected with one output terminal, respectively, of the bistable circuit of the preceding stage, the other input terminal of the gates of the first stage being connected, respectively, to said output terminal of said sampling and modulating means and to the output terminal of said inverter, the output terminals of each of said gates being connected, respectively, with the input terminals of the bistable circuit of the corresponding stage.

Claim 8

A multicorrelator according to claim 2, wherein said reversing unit comprises, for each of said n switches, a bistable circuit with an input terminal connected to said output terminal of said sampling and modulating means, for receiving said succession of pulses, a first output terminal delivering said pulses and a second output terminal delivering a succession of pulses corresponding to the absence of pulses in the received succession of pulses, and wherein each of said switches comprises two transistors having a common collector, a common load resistor connected with the emitters of said transistors, the output terminal of said switch being collected from the emitters of said transistors and a diode for each of said transistors receiving the output of said first and said second output terminal of said bistable circuit respectively, the base of each of said transistors being connected, on the one hand, to the corresponding diode and, on the other hand, to said second general input receiving said second voltage.

Claim 9

A multicorrelator according to claim 6, further comprising a transistor connecting the base of each of said two transistors with said first and said second signal input of said n switches.

Claim 10

A multicorrelator according to claim 2, wherein said sampling and modulating means comprises a sawtooth signal generator adapted to operate at a frequency equal to the frequency of said shifting register divided by an integer, an adding device for adding together the sawtooth voltage supplied by said generator and said first voltage and a sign detector connected to the output of said adding device.