Patent US1419684A successfully refreshed from Google Patents.
Patent EP0099160A2 successfully refreshed from Google Patents.
EP0099160A2
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Moving target indication system
Assignee: Philips Electronics UK Ltd
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Filing: 1983-07-13
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Granted: —
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Expires: 2003-07-13
Abstract
Abstract In order that it should respond satisfactorily to substantially all moving targets within range (without exhibiting "blind speeds") and ignore all stationary targets, a moving target indication system comprises an FM continuous wave radar system in the form of an oscillator (1) the output frequency of which is swept by the output signal of a triangular-wave generator (19). The oscillator output signal is fed to an aerial (3) via a circulator (4) and also to a first input (6) of a mixer (7) a second input (8) of which is supplied with the return signal from the aerial. The respective output waveforms of the mixer occurring for sweeps of the oscillator frequency in the two senses, are, in a further circuit (11), subtracted one from the other after effectively time-reversing one of them, and the resulting difference waveform is analysed in a Fast Fourier Transform calculating circuit (15). The triangular-wave generator (19) may be replaced by a sawtooth-wave generator, in which case the effective time-reversal in the further circuit (11) should be omitted.
Inventors
- 👤 Andrew Gerald Stove
- 👤 Richard Paul Vincent
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 15:24
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/50; G01S13/52; G01S13/536
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
135 words
A moving target indication system comprising a variable-frequency oscillator the output of which is coupled to an aerial, means for repeatedly sweeping the output frequency of said oscillator from a first value to a second value, a mixer circuit to a first input of which the output of said oscillator is coupled and to a second input of which an aerial is coupled, and a signal storage and processing arrangement to an input of which the output of the mixer circuit is coupled, said signal storage and processing arrangement comprising means for producing an output signal which is representative of the waveforms (if any) which would be obtained by subtracting from each other the input waveforms to said arrangement arising from successive sweeps of the oscillator frequency from said first value to said second value.
Claim 2
Dependent Claim
135 words
A moving target indication system comprising a variable-frequency oscillator the output of which is coupled to an aerial, means for repeatedly sweeping the output frequency of said oscillator from a first value to a second value, a mixer circuit to a first input of which the output of said oscillator is coupled and to a second input of which an aerial is coupled, and a signal storage and processing arrangement to an input of which the output of the mixer circuit is coupled, said signal storage and processing arrangement comprising means for producing an output signal which is representative of the waveforms (if any) which would be obtained by subtracting from each other the input waveforms to said arrangement arising from successive sweeps of the oscillator frequency from said first value to said second value.
Claim 3
Dependent Claim
170 words
A moving target indication system comprising a variable-frequency oscillator the output of which is coupled to an aerial, means for repeatedly sweeping the output frequency of said oscillator in alternating senses between first and second values, a mixer circuit to a first input of which the output of said oscillator is coupled and to a second input of which an aerial is coupled, and a signal storage and processing arrangement to an input of which the output of the mixer circuit is coupled, said signal storage and processing arrangement comprising means for producing an output signal which is representative of the waveforms (if any) which would be obtained by subtracting from each other the input waveforms to said arrangement arising from sweeps of the oscillator frequency between said first and second values in one sense and the input waveforms to said arrangement arising from sweeps of the oscillator frequency between said first and second values in the other sense after the latter input waveforms have been put into time-reversed form.
Claim 4
Dependent Claim
170 words
A moving target indication system comprising a variable-frequency oscillator the output of which is coupled to an aerial, means for repeatedly sweeping the output frequency of said oscillator in alternating senses between first and second values, a mixer circuit to a first input of which the output of said oscillator is coupled and to a second input of which an aerial is coupled, and a signal storage and processing arrangement to an input of which the output of the mixer circuit is coupled, said signal storage and processing arrangement comprising means for producing an output signal which is representative of the waveforms (if any) which would be obtained by subtracting from each other the input waveforms to said arrangement arising from sweeps of the oscillator frequency between said first and second values in one sense and the input waveforms to said arrangement arising from sweeps of the oscillator frequency between said first and second values in the other sense after the latter input waveforms have been put into time-reversed form.
Claim 5
Dependent Claim
122 words
A system as claimed in Claim 1 or Claim 2, wherein said signal storage and processing arrangement comprises signal sampling, storage and differencing means for periodically sampling the input waveforms to the arrangement arising from alternate sweeps of the oscillator frequency, storing the samples thus taken, correspondingly periodically sampling the input waveforms to the arrangement arising from the other sweeps of the oscillator frequency, and calculating the differences between the samples taken for each said other sweep and the stored samples taken for the immediately preceding sweep in such manner that each difference is calculated from samples which arose from the same frequency being applied to the first input of the mixer, and Fast Fourier Transform calculating means for processing said differences.
Claim 6
Dependent Claim
44 words
A system as claimed in Claim 1 or in Claim 3, when appended to Claim 1, wherein the means for repeatedly sweeping the oscillator output frequency comprise a sawtooth-wave generator the output of which is coupled to a frequency control input of the oscillator.
Claim 7
Dependent Claim
44 words
A system as claimed in Claim 2, or in Claim 3 when appended to Claim 2, wherein the means for repeatedly sweeping the oscillator output frequency comprises a triangular-wave generator the output of which is coupled to a frequency control input of the oscillator.
References Cited (Backward Citations)
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