US4019185A — Phase modulation apparatus

Claim 1

Independent Claim 292 words

Phase modulation apparatus for an interrupted carrier-wave coherent radar comprising; carrier-wave generator means for generating a carrier-wave signal of a predetermined frequency during transmit periods and having signal output means for connection to an aerial; transmit/receive switch means connected to a power supply control input of the carrier-wave generator means; pulse generator means connected to a control input of the transmit/receive switch means for producing alternately transmit pulses and receive pulses of predetermined and non-overlapping periods, each of said transmit pulses being operative to cause the transmit/receive switch means to switch on a power supply to the carrier-wave generator means for a transmit period and each of said receive pulses being operative to cause the transmit/receive switch means to switch off the power supply to the carrier-wave generator means for a receive period; a delay line coupled at one end to the signal output means of the carrier-wave generator means; reflector means at the other end of the delay line for reflecting signals produced by the carrier-wave generator means during a transmit period and travelling in the delay line; and, modulation signal generator means connected to the reflector means and synchronously connected to the pulse generator means for controlling the reflecting actions of the reflector means so that signals travelling in the delay line are reflected with a phase-shift dependent on a modulation signal produced by the modulation signal generator means and arrive back at the signal output means substantially at but not after the commencement of the next transmit period, the phase of the reflected signal determining by injection phase-locking the phase of the carrier-wave signal produced by the carrier-wave generator means during a transmit period as compared with the phase of the carrier-wave signal produced during the preceding transmit period.

Claim 2

Dependent Claim 292 words

Phase modulation apparatus for an interrupted carrier-wave coherent radar comprising; carrier-wave generator means for generating a carrier-wave signal of a predetermined frequency during transmit periods and having signal output means for connection to an aerial; transmit/receive switch means connected to a power supply control input of the carrier-wave generator means; pulse generator means connected to a control input of the transmit/receive switch means for producing alternately transmit pulses and receive pulses of predetermined and non-overlapping periods, each of said transmit pulses being operative to cause the transmit/receive switch means to switch on a power supply to the carrier-wave generator means for a transmit period and each of said receive pulses being operative to cause the transmit/receive switch means to switch off the power supply to the carrier-wave generator means for a receive period; a delay line coupled at one end to the signal output means of the carrier-wave generator means; reflector means at the other end of the delay line for reflecting signals produced by the carrier-wave generator means during a transmit period and travelling in the delay line; and, modulation signal generator means connected to the reflector means and synchronously connected to the pulse generator means for controlling the reflecting actions of the reflector means so that signals travelling in the delay line are reflected with a phase-shift dependent on a modulation signal produced by the modulation signal generator means and arrive back at the signal output means substantially at but not after the commencement of the next transmit period, the phase of the reflected signal determining by injection phase-locking the phase of the carrier-wave signal produced by the carrier-wave generator means during a transmit period as compared with the phase of the carrier-wave signal produced during the preceding transmit period.

Claim 3

Dependent Claim 50 words

Phase modulation apparatus as claimed in claim 1 and wherein the reflector means comprises a varactor, the instantaneous capacitance of which is determined by the instantaneous magnitude of the modulation signal produced by the modulation signal generator means, said capacitance determining the particular phase shift given to the reflected signals.

Claim 4

Dependent Claim 60 words

Phase modulation apparatus as claimed in claim 1 and wherein the modulation signal generator means comprises binary code generator means for generating a modulation signal comprising a predetermined sequence of binary pulses and the reflector means comprises means for reflecting signals travelling in the delay line with a corresponding sequence of one and the other of two predetermined phase shifts.

Claim 5

Dependent Claim 34 words

Phase modulation apparatus as claimed in claim 3 and wherein the reflector means comprises a pin-diode which presents, in the corresponding sequence, a short-circuit and an open-circuit at the end of the delay line.

Claim 6

Dependent Claim 135 words

Phase modulation apparatus as claimed in claim 1 and wherein the carrier-wave generator means comprises means for generating a microwave frequency carrier-wave, and wherein the apparatus further comprises signal mixer means for producing a signal of a first frequency suitable for application to said delay line, said signal mixer means being coupled at one input to the signal output means of the carrier-wave generator means, is connected at a further input to local oscillator means for producing a signal at a second frequency, and is connected at an output to said one end of the delay line, said second frequency being chosen such that when the signal from the local oscillator means is mixed in the signal mixer means with the microwave frequency carrier-wave the signal mixer means produces said first frequency at its output.

Claim 7

Dependent Claim 96 words

Phase modulation apparatus as claimed in claim 3 and wherein the pulse generator means produces a continuous stream of equally spaced and equal duration pulses, the sum of the durations of one pulse and one space being of one bit duration, and wherein the delay line is a surface-wave acoustic delay line of a length equivalent to a delay of a half-bit duration and the binary code generator means is connected to said pulse generator means so that the sequence of binary pulses is synchronized with the on and off switching operations of the switch means.

Claim 8

Dependent Claim 47 words

Phase modulation apparatus as claimed in claim 6 and wherein the pulses produced by said pulse generator means are such that the duration for which the carrier-wave generator means is switched off by said switch means is longer than the duration for which it is switched on.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1980-04-18	1980-10-18	1981-04-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1984-04-18	1984-10-18	1985-04-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1988-04-18	1988-10-18	1989-04-19	$7700.00	Window Closed / Lapsed

Phase modulation apparatus

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