Patent US4780837A successfully refreshed from Google Patents.
US4780837A
Expired / Lapsed
US
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Doppler signal frequency converter
Assignee: Hitachi Ltd
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Filing: 1985-06-19
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Granted: 1988-10-25
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Expires: 2005-06-19
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
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:43
CPC Classifications
G; G01; G01S; G01S15/00; G01S15/02; G01S15/50; G01S15/58; G01S15/582; G01S15/584
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
143 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 a repetition period is mixed with a complex reference signal and demodulated to convert the Doppler signal to an output complex signal, a delay line which delays an 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 input complex signal which has been delayed by the delay line and the output complex signal, whereby the Doppler signal obtained from the object is converted to Doppler signals of frequencies which enable a wide range of velocity components to be detected.
Claim 2
Dependent Claim
143 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 a repetition period is mixed with a complex reference signal and demodulated to convert the Doppler signal to an output complex signal, a delay line which delays an 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 input complex signal which has been delayed by the delay line and the output complex signal, whereby the Doppler signal obtained from the object is converted to Doppler signals of frequencies which enable a wide range of velocity components to be detected.
Claim 3
Dependent Claim
65 words
A Doppler signal frequency converter according to claim 1 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 outputted by said complex multiplier, and a divider which divides the output conjugate products and complex products of said complex multiplier by the output from said root calculator.
Claim 4
Dependent Claim
188 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 which has been split into two signals by a band pass filter having different pass bands is mixed with complex reference signals having higher and lower frequencies than a carrier signal of said Doppler signal and demodulated to convert the Doppler signal to a plurality of complex signals, a complex multiplier which computes the conjugate products and the complex products of said plurality of complex signals, and 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 outputted by said complex multiplier and a divider which divides the output conjugate products and complex products of said complex multiplier by the output from said root calculator, 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
188 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 which has been split into two signals by a band pass filter having different pass bands is mixed with complex reference signals having higher and lower frequencies than a carrier signal of said Doppler signal and demodulated to convert the Doppler signal to a plurality of complex signals, a complex multiplier which computes the conjugate products and the complex products of said plurality of complex signals, and 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 outputted by said complex multiplier and a divider which divides the output conjugate products and complex products of said complex multiplier by the output from said root calculator, 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 6
Dependent Claim
35 words
A Doppler signal frequency converter according to claims 1 or 3 wherein the Doppler signal is picked up by a plurality of different receiving frequency bands which are repetitively switched synchronously at a set frequency.
Claim 7
Dependent Claim
29 words
A Doppler signal frequency converter according to claim 1 or 3 wherein the complex signal converters repetitively change the frequency of complex reference signals synchronously at a set frequency.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-10-25 | 1992-04-25 | 1992-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-25 | 1996-04-25 | 1996-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-25 | 2000-04-25 | 2000-10-25 | $7700.00 | Window Closed / Lapsed |