US5387883A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Quadrature modulator having controlled phase shifter
Assignee: NEC Corp
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Filing: 1993-05-20
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Granted: 1995-02-07
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Expires: 2013-05-20
Abstract
Abstract A quadrature modulation circuit of the present invention has a phase shifter whose shifting amount is fixed at 90 degrees, a minute amount-phase shifter whose shifting amount is variable, a detector for detecting a RF signal supplied from the quadrature modulation circuit by a direct voltage signal, and a control circuit for generating a control signal in accordance with a direct voltage signal from the detector. Phase shifting amount of the minute amount-phase shifter is adjusted by the control signal whereby a total amount of the phase shifting is maintained at 90 degrees.
Inventors
- 👤 Hideki Ueda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:15
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/32; H04L27/34; H04L27/36; H04L27/362; H04L27/364; H03; H03C; H03C3/00; H03C3/38; H03C3/40
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
200 words
A quadrature modulation circuit, comprising: means for supplying a local signal and two baseband signals; means for dividing said local signal into two local signals; means for shifting a phase of at least one of said two local signals to provide a relative phase difference of 90 degrees therebetween; a first mixer for combining said first baseband signal with a first one of said two local signals, whereby a first combined signal is obtained; a second mixer for combining said second baseband signal with a second one of said two local signals, whereby a second combined signal is obtained; means for adding said first and second combined signals; and controlling means for controlling said shifting means in accordance with an output signal of said adding means, whereby said two local signals are adjusted to have a relative phase difference of 90 degrees, said controlling means comprises a band-pass filter for limiting a band of said output signal of said adding means, a detector for detecting a signal passing through said band-pass filter by a direct voltage signal, and a control circuit for controlling a shifting amount of said shifting means in accordance with said direct voltage signal from said detector.
Claim 2
Dependent Claim
200 words
A quadrature modulation circuit, comprising: means for supplying a local signal and two baseband signals; means for dividing said local signal into two local signals; means for shifting a phase of at least one of said two local signals to provide a relative phase difference of 90 degrees therebetween; a first mixer for combining said first baseband signal with a first one of said two local signals, whereby a first combined signal is obtained; a second mixer for combining said second baseband signal with a second one of said two local signals, whereby a second combined signal is obtained; means for adding said first and second combined signals; and controlling means for controlling said shifting means in accordance with an output signal of said adding means, whereby said two local signals are adjusted to have a relative phase difference of 90 degrees, said controlling means comprises a band-pass filter for limiting a band of said output signal of said adding means, a detector for detecting a signal passing through said band-pass filter by a direct voltage signal, and a control circuit for controlling a shifting amount of said shifting means in accordance with said direct voltage signal from said detector.
Claim 3
Dependent Claim
220 words
A quadrature modulation circuit, comprising: means for supplying a local signal and two baseband signals; means for dividing said local signal into two local signals; means for shifting a phase of at least one of said two local signals to provide a relative phase difference of 90 degrees therebetween; a first mixer for combining said first baseband signal with a first one of said two local signals, whereby a first combined signal is obtained; a second mixer for combining said second baseband signal with a second one of said two local signals, whereby a second combined signal is obtained; means for adding said first and second combined signals; and controlling means for controlling said shifting means in accordance with an output signal of said adding means, whereby said two local signals are adjusted to have a relative phase difference of 90 degrees, said controlling means comprises a band-pass filter for limiting a band of said output signal of said adding means, a detector for detecting a signal passing through said band-pass filter by a direct voltage signal, and a control circuit for controlling a shifting amount of said shifting means in accordance with said direct voltage signal from said detector; said control circuit controlling a shifting amount of said shifting means to minimize said direct voltage signal from said detector.
Claim 4
Dependent Claim
220 words
A quadrature modulation circuit, comprising: means for supplying a local signal and two baseband signals; means for dividing said local signal into two local signals; means for shifting a phase of at least one of said two local signals to provide a relative phase difference of 90 degrees therebetween; a first mixer for combining said first baseband signal with a first one of said two local signals, whereby a first combined signal is obtained; a second mixer for combining said second baseband signal with a second one of said two local signals, whereby a second combined signal is obtained; means for adding said first and second combined signals; and controlling means for controlling said shifting means in accordance with an output signal of said adding means, whereby said two local signals are adjusted to have a relative phase difference of 90 degrees, said controlling means comprises a band-pass filter for limiting a band of said output signal of said adding means, a detector for detecting a signal passing through said band-pass filter by a direct voltage signal, and a control circuit for controlling a shifting amount of said shifting means in accordance with said direct voltage signal from said detector; said control circuit controlling a shifting amount of said shifting means to minimize said direct voltage signal from said detector.
References Cited (Backward Citations)
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