Phase-coded pulse compression apparatus

Claim 2

In a phase-coded pulse-compression type pulsed radar system employing a modified code which, when delayed by a preselected number of code bits and combined with the undelayed code, provides a preselected code, a receiver comprising: A phase sensitive detector, both inputs of which are responsive to received echoes of a transmitted modified code; and Delay means interposed at one of said detector inputs for providing a time delay corresponding to said preselected number of code bits of said transmittal code; Whereby a preselectively phase-coded video detected signal output is provided.

Claim 3

In a phase-coded pulse-compression type pulsed radar system employing a modified transmittal code which, when delayed by one code bit, and combined with the undelayed code, provides a preselected code, a receiver comprising: A phase sensitive detector, both inputs of which are responsive to received echoes of a transmitted modified code; and Delay means interposed at one of said detector inputs for providing a time delay corresponding to one code bit of said transmittal code; Whereby a preselectively phase-coded video detected signal output is provided.

Claim 4

In a phase-coded pulse-compression type pulsed radar system employing a modified transmittal code which, when delayed by one code bit, and combined with the undelayed code, provides a preselected code, a receiver comprising: A phase sensitive detector, both inputs of which are responsive to received echoes of a transmitted modified code; and Delay means interposed at one of said detector inputs for providing a time delay corresponding to one code bit of said transmittal code; Whereby a preselectively phase-coded video detected signal output is provided.

Claim 5

The device of claim 2 in which said radar system is a monopulse receiver of the sum and difference type, a first input of said detector being responsive to the sum of said received echoes and a second input of said detector being responsive to the difference between said received echoes, whereby a preselectively phase-coded monopulse difference signal output is provided.

Claim 6

The device of claim 3 in which there is provided means for detecting the sense of the angle-off-boresight of a detected target providing said echoes and comprising said detector and said delay means.

Claim 7

In a phase-coded pulse compression type pulsed radar system employing a modified code which, when delayed by one code bit, and combined with the undelayed code, provides a preselected code, a receiver comprising: A phase detector, both inputs of which are commonly responsive to received echoes of a transmitted modified code One-bit delay means interposed at one of said detector inputs, whereby a preselectively coded bipolar video detected signal is provided at the output of said phase detector.

Claim 8

In a phase-coded pulse compression type pulsed radar system employing a modified code which, when delayed by one code bit, and combined with the undelayed code, provides a preselected code, a receiver comprising: A phase detector, both inputs of which are commonly responsive to received echoes of a transmitted modified code One-bit delay means interposed at one of said detector inputs, whereby a preselectively coded bipolar video detected signal is provided at the output of said phase detector.

Claim 9

In a phase-coded pulse compression type pulsed radar system, the combination comprising Means for transmitting a modified code which, when delayed by one code bit and combined with the undelayed modified code, provides a preselected code, Receiving means responsive to echoes of said transmitted code, and including a phase detector, both inputs of which are commonly responsive to said received echoes; and Delay means interposed at one of said detector inputs for providing a time delay corresponding to one code bit of said transmitted code.

Claim 10

In a phase-coded pulse compression type pulsed radar system, the combination comprising Means for transmitting a modified code which, when delayed by one code bit and combined with the undelayed modified code, provides a preselected code, Receiving means responsive to echoes of said transmitted code, and including a phase detector, both inputs of which are commonly responsive to said received echoes; and Delay means interposed at one of said detector inputs for providing a time delay corresponding to one code bit of said transmitted code.

Claim 11

The device of claim 6 in which there is further provided video decoding means responsive to the preselectively coded bipolar video detected output of said phase detector for combining the in-phase and anti-phase bits of said bipolar video detected signal to provide a received radar signal having improved range resolution.

Claim 12

The device of claim 6 in which there is further provided video decoding means comprising A tapped delay line, the delay intervals between successive taps of which corresponding to one bit of said transmitted code, and Signal combining means to respectively sum the corresponding in-phase and anti-phase bits of the video output of said detector, and subtractively combine said summed signals.

Claim 13

The device of claim 6 in which there is further provided A tapped delay line having a plurality of taps corresponding to the number of bits in said preselected code, the delay interval between successive taps corresponding to one bit of said transmitted code, First signal combining means responsive to said taps of said delay line for combining outputs representing code bits having a first selected sense, Second signal combining means responsive to said taps of said delay line for combining outputs representing code bits having a second selected sense opposed to said first sense, and Differential signal combining meaning means responsive to said first and second combining means for providing an output indicative of the difference therebetween.

Claim 14

In a phase-coded pulse compression type radar system employing a modified code which, when delayed by one code bit and combined with the undelayed code, provides a preselected code, monopulse receiving means for providing monopulse sum and difference signals respectively indicative of the sum and difference between received echoes of a transmitted modified code and comprising A phase sensitive detector having a first and second input respectively responsive to said monopulse sum and difference signals; and Delay means interposed at one of said detector inputs for providing a time delay corresponding to one code bit of said transmitted code, Whereby the output of said detector is a video-detected monopulse difference signal phase-coded in accordance with said preselected code and having a phase sense indicative of the angle-off-bore-sight of a detected target producing said echoes.

Claim 15

In a phase-coded pulse compression type radar system employing a modified code which, when delayed by one code bit and combined with the undelayed code, provides a preselected code, monopulse receiving means for providing monopulse sum and difference signals respectively indicative of the sum and difference between received echoes of a transmitted modified code and comprising A phase sensitive detector having a first and second input respectively responsive to said monopulse sum and difference signals; and Delay means interposed at one of said detector inputs for providing a time delay corresponding to one code bit of said transmitted code, Whereby the output of said detector is a video-detected monopulse difference signal phase-coded in accordance with said preselected code and having a phase sense indicative of the angle-off-bore-sight of a detected target producing said echoes.

Claim 16

The device of claim 10 in which there is further provided A tapped delay line having a plurality of taps each corresponding to a successive one of the bits in said preselected code, the delay interval between successive taps corresponding to the bit time of said transmitted code, First signal combining means responsive to said taps of said delay line for combining outputs representing code bits having a first selected sense, Second signal combining means responsive to said taps of said delay line for combining outputs representing code bits having a second selected sense opposed to said first sense, and Differential signal combining meaning means responsive to said first and second combining means for providing an output indicative of the difference therebetween.

Claim 17

An auto coherent phase coding circuit for connecting a source of received echo signals from radar transmission of a series of wide, coded pulses to a decoder unit, comprising, means for modifying said coded pulses, phase detector means, a direct path from said source of modified coded pulse signals to said phase detector means, a delay path from said source of modified coded signals to said phase detector means and connected in parallel with said direct path, delay means interposed in said delay path for delaying said modified coded pulse signals, means in said phase detector means whereby said modified coded pulse when phase detected against itself produces the original series of coded pulse free of any Doppler frequency shift effects, and an output path from said phase detector means to said decoder unit whereby when the pulses from the output of said phase detector means are decoded said original wide pulse is collapsed into narrow pulse with an accompanying increase in effective peak signal.

Claim 18

An auto coherent phase coding circuit for connecting a source of received echo signals from radar transmission of a series of wide, coded pulses to a decoder unit, comprising, means for modifying said coded pulses, phase detector means, a direct path from said source of modified coded pulse signals to said phase detector means, a delay path from said source of modified coded signals to said phase detector means and connected in parallel with said direct path, delay means interposed in said delay path for delaying said modified coded pulse signals, means in said phase detector means whereby said modified coded pulse when phase detected against itself produces the original series of coded pulse free of any Doppler frequency shift effects, and an output path from said phase detector means to said decoder unit whereby when the pulses from the output of said phase detector means are decoded said original wide pulse is collapsed into narrow pulse with an accompanying increase in effective peak signal.

Claim 19

The circuit as described in claim 12 wherein said delay means comprises means for delaying said modified coded pulses by one time increment.