Doppler signal simulator

Claim 2

Doppler Signal Simulation apparatus comprising: a. means to generate wide band white noise; b. means to generate a plurality of doppler return signals, including signals of at least two different frequencies; c. a plurality of summing means to sum said white noise with each of said plurality of doppler signals; and d. means to provide as a further input to at least one of said summing means at least a portion of another of said doppler signals which is at a different frequency to thereby simulate an image beam signal.

Claim 3

Apparatus to produce a signal simulating a doppler return signal comprising: a. a white noise generator; b. means to generate a first pulse train at the desired center frequency of the doppler signal; and c. a first commutation filter including means to divide said pulse train into four pulse trains each of which will have pulses which are on for a different 90* of full 360* of each pulse of said first pulse train, a capacitive commutation filter element, and a resistive portion said commutating filter having the output of said white noise generator as a signal input with said four pulse trains as switching inputs said commutation providing the simulated doppler return signal at its output.

Claim 4

Apparatus to produce a signal simulating a doppler return signal comprising: a. a white noise generator; b. means to generate a first pulse train at the desired center frequency of the doppler signal; and c. a first commutation filter including means to divide said pulse train into four pulse trains each of which will have pulses which are on for a different 90* of full 360* of each pulse of said first pulse train, a capacitive commutation filter element, and a resistive portion said commutating filter having the output of said white noise generator as a signal input with said four pulse trains as switching inputs said commutation providing the simulated doppler return signal at its output.

Claim 5

The invention according to claim 2 and further including a second commutating filter in series with the output of said first commutating filter.

Claim 6

The invention according to claim 3 and further including means to vary the time constant to said first and second commutating filters to thereby vary the bandwidth of the output.

Claim 7

The invention according to claim 2 wherein said noise generator comprises a pseudo random code generator.

Claim 8

A doppler signal simulator comprising: a. means to generate a doppler composite signal including at least a first doppler return signal at a first frequency and broad band white noise; b. means to generate a second doppler return signal at a second frequency; and c. means to sum at least a portion of said second doppler signal with said composite signal to thereby simulate an image beam.

Claim 9

A doppler signal simulator comprising: a. means to generate a doppler composite signal including at least a first doppler return signal at a first frequency and broad band white noise; b. means to generate a second doppler return signal at a second frequency; and c. means to sum at least a portion of said second doppler signal with said composite signal to thereby simulate an image beam.

Claim 10

A doppler signal simulator comprising: a. means to generate a plurality of frequencies representing the center frequencies of each of a plurality of doppler return signals obtained from different beams transmitted in different directions; b. first means to generate wide band white noise; c. a plurality of commutating filters all having as inputs said white noise and each having one of said plurality of center frequencies as an input and providing an output which simulates a doppler signal with a center frequency equal to its input; d. means to generate a plurality of beam switching outputs said outputs occuring in sequence; e. multiplexing means having the outputs from said plurality of filters as signal inputs and said beam switching inputs as control inputs to provide each of said signal inputs as an output in sequential manner in response to corresponding beam switching control inputs.

Claim 11

A doppler signal simulator comprising: a. means to generate a plurality of frequencies representing the center frequencies of each of a plurality of doppler return signals obtained from different beams transmitted in different directions; b. first means to generate wide band white noise; c. a plurality of commutating filters all having as inputs said white noise and each having one of said plurality of center frequencies as an input and providing an output which simulates a doppler signal with a center frequency equal to its input; d. means to generate a plurality of beam switching outputs said outputs occuring in sequence; e. multiplexing means having the outputs from said plurality of filters as signal inputs and said beam switching inputs as control inputs to provide each of said signal inputs as an output in sequential manner in response to corresponding beam switching control inputs.

Claim 12

The invention according to claim 7 and further including means to select system test or tracker test and wherein said means to generate a plurality of frequencies is adapted to generate two sets of a plurality frequencies in response to said selection means, one set representing the frequencies found at the input to a doppler system post if stage in response to a system test selection and a second set representing the frequencies found at the tracker input of a doppler system, in response to a tracker test selection.

Claim 13

The invention according to claim 8 wherein said frequency generation means comprises: a. a first oscillator b. a second oscillator, c. a plurality of divide by N counters, and d. meanS to provide the output of one of said first and second oscillators to said plurality of counters in response to said selection means.

Claim 14

The invention according to claim 9 wherein said a plurality of divide by N counters is greater than the plurality of beams and further including decoding logic to select from said plurality of counters a number of signals equal to said plurality of beams and means to provide a binary signal to said decoding logic to make said selection.

Claim 15

The invention according to claim 10 wherein said means to provide a binary signal comprises a switch.

Claim 16

The invention according to claim 10 wherein said means to provide a binary signal comprises a digital computer.

Claim 17

The invention according to claim 10 and further including a plurality of voltage controlled oscillators each having a separate control input, selection input means, and logic means having the outputs of said voltage controlled oscillators and said the outputs of decoding means as inputs and providing one of said inputs as outputs in response to said selection means.

Claim 18

The invention according to claim 7 wherein said frequency generation means comprise a plurality of voltage controlled oscillators.

Claim 19

The invention according to claim 7 and further including second means to generate white noise and means to add said white noise to the output of each of said commutating filters.

Claim 20

The invention according to claim 15 wherein each of said first and second white noise generators comprises a pseudo random code generator.

Claim 21

The invention according to claim 7 wherein each of said commutating filters further includes means to provide one of several time constants and further including input means to select one of said time constants.

Claim 22

The invention according to claim 17 wherein said means to provide several time constants comprise a plurality of resistors which may be selectively connected into said filter by operation of a plurality of associated relays and said means to select comprise means to operate said relays.

Claim 23

The invention according to claim 7 and further including means to generate a leakage signal and means to add said leakage signal to each of said filter outputs.

Claim 24

The invention according to claim 19 and further including means to add the output of one of said filters to that of another of said filters.

Claim 25

The invention according to claim 19 and further including means to control the amplitudes of said leakage signal, a plurality of means to control the amplitudes of said filter outputs and means to control the amplitude of the output of said multiplexer.

Claim 26

The invention according to claim 21 wherein said leakage signal generator generates a plurality of signals all at the same frequency but at different phase angles, a different one of said signals being added to each of said plurality of filter outputs and said leakage amplitude control means include a separate amplitude control means for each of said signals.

Claim 27

The invention according to claim 7 and further including, in said multiplexer, means to select any one input signal as a constant output in response to a control input.

Claim 28

A doppler signal simulator to simulate the signal input to the post IF or tracker of a doppler navigation system of the type which transmits X beams sequentially in different directions obtaining thereby in sequence X different doppler return signals said apparatus comprising: a. means to generate at least X different frequencies representing doppler center frequencies; b. at least one pseudo random code generator generating white noise; c. X commutating filters having the output of said code generator as signal input and one of said X frequencies as a switching input; d. X first amplitude control means having the outputs of said X filters as respective inputs; e. means to generate X leakage signals all having the same frequency but each having a different phase, f. X second amplitude control meAns having said X leakage signals as respective inputs; g. summing means to sum the respective outputs of said first and second amplitude control means and the output of said pseudo random code generator; h. means to generate X pulse trains, the pulses on respective trains occuring in sequence; i. a multiplexer having the outputs of said X summing means as signal inputs and said X pulse trains as switching inputs to sequentially switch said X signal inputs to the output of said multiplexer; j. third amplitude control means having the output of said multiplexer as an input; and k. filter means having the output of said amplitude control means as an input and providing its output as the output of said simulator.

Claim 29

A doppler signal simulator to simulate the signal input to the post IF or tracker of a doppler navigation system of the type which transmits X beams sequentially in different directions obtaining thereby in sequence X different doppler return signals said apparatus comprising: a. means to generate at least X different frequencies representing doppler center frequencies; b. at least one pseudo random code generator generating white noise; c. X commutating filters having the output of said code generator as signal input and one of said X frequencies as a switching input; d. X first amplitude control means having the outputs of said X filters as respective inputs; e. means to generate X leakage signals all having the same frequency but each having a different phase, f. X second amplitude control meAns having said X leakage signals as respective inputs; g. summing means to sum the respective outputs of said first and second amplitude control means and the output of said pseudo random code generator; h. means to generate X pulse trains, the pulses on respective trains occuring in sequence; i. a multiplexer having the outputs of said X summing means as signal inputs and said X pulse trains as switching inputs to sequentially switch said X signal inputs to the output of said multiplexer; j. third amplitude control means having the output of said multiplexer as an input; and k. filter means having the output of said amplitude control means as an input and providing its output as the output of said simulator.

Claim 30

The invention according to claim 24 wherein each of said amplitude control means comprise an operational amplifier having a fixed feedback resistor and a plurality of inputs resistors and means to selectively cause said input resistors to be placed between the input signal and said amplifier.

Claim 31

The invention according to claim 25 and further including means to select system test or tracker test wherein said means to generate at least X different frequencies is adapted to generate two sets of at least X different frequencies in response to said selection means, one set representing the frequencies found at the input to a doppler system post if stage in response to system test selection and a second set representing the frequencies found at the tracker input of a doppler system, in response to a tracker test selection.

Claim 32

The invention according to claim 26 wherein said frequency generation means comprises: a. a first oscillator b. a second oscillator, c. a plurality of divide by N counters, and d. means to provide the output of one of said first and second oscillators to said plurality of counters in response to said selection means.

Claim 33

The invention according to claim 27 wherein said plurality of divide by N counters is greater than said X beams and further including decoding logic to select from said plurality of counters a number of signals equal to X and means to provide a binary signal to said decoding logic to make said selection.

Claim 34

The invention according to claim 28 and further including a plurality of individually controlled voltage controlled oscillators each having a separate control input, a selection input means and logic means having the outputs of said voltage controlled oscillators and said decoding means as inputs and providing one of said inputs as outputs in response to said selection input means.

Claim 35

The invention according to claim 29 wherein said multiplexer output is provided to a tracker band pass filter and a system band pass filter, the respective simulator outputs being taken from said filters.

Claim 36

The invention according to claim 30 wherein two random code generators are provided, one providing its output to said commutating filters and the other providing its output to said summing means.

Claim 37

The invention according to claim 31 wherein each of said amplitude switches, said frequency selection input, said tracker system made selection input, said bandwidth control inputs are provided by a digital computer.

Claim 38

The invention according to claim 32 wherein said multiplexer comprises a four channel FET switch.