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Title: Doppler frequency radar system with very short pulse modulated high frequency carrier waves
Claims: We claim: 1. A doppler frequency radar system, comprising means for generating a high frequency carrier wave, means for amplitude modulating said carrier wave at a relatively low frequency, means for also amplitude modulating such carrier wave to produce short impulses of relatively high pulse sequence frequency, means for radiating said modulated carrier wave toward a moving object, means for receiving such wave as reflected from such a moving object, means for generating accurate timing pulses, means forming a plurality of distance measuring branch circuits, means operatively connected to said timing pulse generating means, and controlled by such pulses, for operatively connecting the receiving means to the respective branch circuits, operative to distribute said received impulses in accordance with the time relation of the received impulses to the timing pulses, means in each branch circuit for demodulating the pulses appearing therein and to form rough distance measuring pulses, means in each branch circuit forming a coincidence circuit and operatively connected to said timing pulse generating means whereby said coincidence circuit is operable to form, responsive to coincident occurrence of the respective rough distance measuring pulses and the timing pulses fine measuring pulses which assure unequivocal distance indication even in the presence of high pulse sequence frequency. 2. A system according to claim 1, comprising a radar sighting device and means for supplying deflection pulses thereto, the deflection frequency of which is equal to the modulation frequency, the latter being lower than the pulse sequence frequency, so as to extend the indicating range beyond the range which may be calculated from the pulse sequence frequency. 3. A system according to claim 1, wherein said branch circuits each include for the evaluation of the modulation frequency a circuit of the multiar type which produces upon zero passage of the modulation voltage rough distance measuring pulses the lateral position of which depends upon the target distance. 4. A doppler frequency radar system, comprising means for generating a high frequency carrier wave, means for amplitude modulating said wave to form impulses at a relatively high pulse sequence frequency, and means for also amplitude modulating such wave at a relatively low frequency, means for radiating said modulated wave toward a moving object, means for receiving said wave as reflected from such a moving object, means for demodulating the received wave to produce rough but unequivocal distance measuring pulses, means for generating accurate timing pulses at the pulse modulation frequency, means for comparing said timing pulses with said rough distance measuring pulses for coincidence, and means for forming responsive to coincident occurrence of the respective rough distance measuring pulses and the timing pulses, fine measuring pulses which assure unequivocal distance indication even in the presence of high pulse sequence frequency. 5. A system according to claim 4, wherein said means for producing rough distance measuring pulses is constructed to produce rough distance measuring pulses which are of a duration to embrace the respectively cooperating timing pulse, but shorter than would be required to simultaneously embrace two timing pulses. 6. A system according to claim 4, wherein said means for modulating at the pulse sequence frequency is constructed, with a carrier wave length as short as possible within the centimeter or microwave range, to produce a pulse sequence frequency which is so high, for example 25 kilocycles, that the first reactive velocity appears at the upper limit of the measuring range and especially above the maximum radial velocity of the object to be measured. 7. A system according to claim 4, wherein the frequency of said low frequency amplitude modulating means is constructed to modulate at a frequency considerably lower than the pulse sequence frequency. 8. A dopper frequency radar system, comprising means for generating a high frequency carrier wave, means for amplitude modulating said wave to form impulses at a relatively high pulse sequence frequency, and also means for amplitude modulating such wave at a relatively low frequency, means for radiating said modulated wave toward a moving object, means for receiving said wave as reflected from such a moving object and any waves reflected from stationary objects, means for blocking out any waves reflected from stationary objects, means for generating accurate timing pulses at the pulse frequency, means for segregating the respective received pulses as to time, means for demodulating a segregated series of pulses to produce rough but unequivocal distance measuring pulses, means for comparing respective timing pulses with said rough distance measuring pulses for coincidence, and means for forming responsive to coincident occurrence of the respective rough distance measuring pulses and the timing pulses, fine measuring pulses which assure unequivocal distance indication even in the presence of high pulse sequence frequency. 9. A system according to claim 8, wherein said means for producing rough distance measuring pulses is constructed to produce rough distance measuring pulses which are of a duration to embrace the respectively cooperating timing pulse, but shorter than would be required to simultaneously embrace two timing pulses. Other info: Inventors: Wiedemann, Kurt (Munich, DT) Lenz, Karl-Ludwig (Munich-Solln, DT) Application Number: 088581 Filing Date: 1961-02-10 Publication_date: 1976-01-20 Assignee: Siemens & Halske Aktiengesellschaft (Berlin & Munich, DT) Primary Class(es): 342/134 342/136, 342/160 Other Classes: US Patent Ref:
Other Refs: Primary Examiner: Tubbesing, T. H. Assistant Examiner: Attorney: Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson |
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