Patent EP0166392A2 successfully refreshed from Google Patents.
EP0166392A2
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EP
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Doppler signal frequency converter
Assignee: Hitachi Ltd
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Filing: 1985-06-21
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Granted: —
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Expires: 2005-06-21
Abstract
Abstract A Doppler signal frequency converter for use in an apparatus used to detect and measure the velocity of movement of an object by picking up the reflections of ultrasonic waves beamed at the subject of examination. The converter is provided with one or a plurality of complex signal converters, and a complex multiplier which computes the conjugate and complex products of the complex signals. The complex signal converter converts the Doppler signals to a plurality - for example two - complex signals which differ in frequency. By carrying out computations based on the real and imaginary parts of the complex signals, the conjugate and complex products of the two complex signals are obtained. These conjugate and complex products are Doppler signals having a frequency which enables a wide range of velocity components to be detected, the conjugate product enabling the velocity of a distant rapidly-moving object to be measured accurately, while the complex product provides accurate measurement of the velocity of a slow-moving object.
Inventors
- 👤 Kouroku Namekawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 16:20
CPC Classifications
G; G01; G01S; G01S15/00; G01S15/02; G01S15/50; G01S15/58; G01S15/582; G01S15/584
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
109 words
A Doppler signal frequency converter comprising a complex signal converter in which a Doppler signal obtained by picking up and amplifying the reflection of a periodic pulse modulated wave beamed at a moving object is mixed with a complex reference signal and demodulated to convert the Doppler signal to a complex signal, and a complex multiplier which computes the conjugate product and the complex product of said complex signal, whereby the Doppler signal obtained from the object is divided and arithmetically processed into a plurality of complex signals of differing frequencies to thereby obtain Doppler signals of frequencies which enable a wide range of velocity components to be detected.
Claim 2
Dependent Claim
109 words
A Doppler signal frequency converter comprising a complex signal converter in which a Doppler signal obtained by picking up and amplifying the reflection of a periodic pulse modulated wave beamed at a moving object is mixed with a complex reference signal and demodulated to convert the Doppler signal to a complex signal, and a complex multiplier which computes the conjugate product and the complex product of said complex signal, whereby the Doppler signal obtained from the object is divided and arithmetically processed into a plurality of complex signals of differing frequencies to thereby obtain Doppler signals of frequencies which enable a wide range of velocity components to be detected.
Claim 3
Dependent Claim
105 words
A Doppler signal frequency converter comprising a plurality of complex signal converters in which a Doppler signal obtained by picking up and amplifying the reflections of a periodic pulse modulated wave beamed at a moving object is mixed with complex reference signals and demodulated to convert the Doppler signal to a plurality of complex signals, and a complex multiplier which computes the conjugate products and the complex products of said plurality of complex signals, whereby the Doppler signal obtained from the object is arithmetically processed into a plurality of complex signals of differing frequencies which enable a wide range of velocity components to be detected.
Claim 4
Dependent Claim
105 words
A Doppler signal frequency converter comprising a plurality of complex signal converters in which a Doppler signal obtained by picking up and amplifying the reflections of a periodic pulse modulated wave beamed at a moving object is mixed with complex reference signals and demodulated to convert the Doppler signal to a plurality of complex signals, and a complex multiplier which computes the conjugate products and the complex products of said plurality of complex signals, whereby the Doppler signal obtained from the object is arithmetically processed into a plurality of complex signals of differing frequencies which enable a wide range of velocity components to be detected.
Claim 5
Dependent Claim
44 words
A Doppler signal frequency converter according to claims 1 or 2 provided with band pass filters having different pass bands whereby the Doppler signal obtained from the object is split into two signals which are converted into complex signals by two complex signal converters.
Claim 6
Dependent Claim
51 words
A Doppler signal frequency converter according to claims 1 or 2 wherein the Doppler signal obtained from the object is converted into two complex signals by two complex signal converters which perform the complex conversion using reference waves having frequencies that are higher and lower than the Doppler signal carrier frequency.
Claim 7
Dependent Claim
134 words
A Doppler signal frequency converter comprising a plurality of complex signal converters in which a Doppler signal obtained by picking up and amplifying the reflection of a periodic pulse modulated wave beamed at a moving object at periods which are integer multiples of the repetition period is mixed with'a complex reference signal and demodulated to convert the Doppler signal to a complex signal, a delay line which delays the input complex signal by a period which is an integer multiple of the repetition period, and a complex multiplier which computes the complex products and the conjugate products of the delay line input complex signal and output complex signal, whereby the Doppler signal obtained from the object are converted to Doppler signals of frequencies which enable a wide range of velocity components to be detected.
Claim 8
Dependent Claim
134 words
A Doppler signal frequency converter comprising a plurality of complex signal converters in which a Doppler signal obtained by picking up and amplifying the reflection of a periodic pulse modulated wave beamed at a moving object at periods which are integer multiples of the repetition period is mixed with'a complex reference signal and demodulated to convert the Doppler signal to a complex signal, a delay line which delays the input complex signal by a period which is an integer multiple of the repetition period, and a complex multiplier which computes the complex products and the conjugate products of the delay line input complex signal and output complex signal, whereby the Doppler signal obtained from the object are converted to Doppler signals of frequencies which enable a wide range of velocity components to be detected.
Claim 9
Dependent Claim
65 words
A Doppler signal frequency converter according to claims 1, 2, 3, 4 or 5 provided with an amplitude calculator comprised of a root calculator which computes the root of the sum of the square of the real parts of the complex signals output by said complex multiplier, and a divider which divides the output of said complex multiplier by the output from said root calculator.
Claim 10
Dependent Claim
33 words
A Doppler signal frequency converter according to claims 1 or 5 wherein the Doppler signal is picked up by a plurality of different receiving bands which are switched synchronously with time division periods.
Claim 11
Dependent Claim
28 words
A Doppler signal frequency converter according to claims 1 or 5 which switches frequencies of complex reference signals having a plurality of frequencies synchronously with time division periods.
References Cited (Backward Citations)
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