US5862466A
Expired / Lapsed
US
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Method and apparatus for automatically balancing a radio-frequency mixer
Assignee: Agilent Technologies Inc
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Filing: 1997-01-09
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Granted: 1999-01-19
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Expires: 2017-01-09
Abstract
Abstract An automatic balancing circuit for a radio frequency mixer which reduces LO-IF signal leakage, as well as minimizing second order harmonic distortion products is described. The circuit couples to in-phase and out-of-phase signal lines originating from the mixer, and comprises a differential gain network, a differential phase shift network and a combiner. The networks operate under the control of a microprocessor, which adjusts the networks so that the LO leakage signals, when combined, are almost completely eliminated.
Inventors
- 👤 Bruce A. Erickson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:20
CPC Classifications
H; H03; H03D; H03D7/00; H03D2200/00; H03D2200/0001; H03D2200/0003; H03D2200/0023; H03D2200/0029; H03D2200/0041; H03D2200/009; H03D7/02; H03D7/14; H03D7/1408; H03D9/00; H03D9/06; H03D9/0608; H03D9/0633
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
173 words
In a spectrum analyzer having a single balanced mixer with a balun for mixing a radio frequency input signal and a local oscillator input signal to produce an intermediate frequency signal, a circuit for minimizing leakage of the local oscillator signal into intermediate frequency circuitry, the circuit comprising: an in-phase signal line and an out-of-phase signal line, the lines being coupled to the balun, the lines carrying an in-phase and an out-of-phase signal, respectively; a differential gain network coupled to the in-phase and out-of-phase signal lines, the differential gain network adjusting the amplitude of the in-phase and out-of-phase signals; a differential phase shift network coupled to the differential gain network, the differential phase shift network receiving the amplitude adjusted in-phase and out-of-phase signals and shifting the signals in phase; a signal combiner coupled to differential phase shift network for combining the amplitude and phase adjusted in-phase and out-of-phase signals; and a microprocessor coupled to the differential gain network and the differential phase shift network for determining and controlling the amplitude and phase adjustments.
Claim 2
Dependent Claim
173 words
In a spectrum analyzer having a single balanced mixer with a balun for mixing a radio frequency input signal and a local oscillator input signal to produce an intermediate frequency signal, a circuit for minimizing leakage of the local oscillator signal into intermediate frequency circuitry, the circuit comprising: an in-phase signal line and an out-of-phase signal line, the lines being coupled to the balun, the lines carrying an in-phase and an out-of-phase signal, respectively; a differential gain network coupled to the in-phase and out-of-phase signal lines, the differential gain network adjusting the amplitude of the in-phase and out-of-phase signals; a differential phase shift network coupled to the differential gain network, the differential phase shift network receiving the amplitude adjusted in-phase and out-of-phase signals and shifting the signals in phase; a signal combiner coupled to differential phase shift network for combining the amplitude and phase adjusted in-phase and out-of-phase signals; and a microprocessor coupled to the differential gain network and the differential phase shift network for determining and controlling the amplitude and phase adjustments.
Claim 3
Dependent Claim
60 words
The circuit of claim 1, wherein the differential gain network comprises: a first and second field effect transistor, the gates of the transistors being respectively coupled to the in-phase and out-of phase signal lines; a current sensing amplifier coupled to the drains of the transistors; and a digital-to-analog converter coupled to both the microprocessor and the gates of the transistors.
Claim 4
Dependent Claim
268 words
In a spectrum analyzer having a single balanced mixer with a balun for mixing a radio frequency in-put signal and a local oscillator input signal to produce an intermediate frequency signal, a circuit for minimizing leakage of the local oscillator signal into intermediate frequency circuitry, the circuit comprising: an in-phase signal line and an out-of-phase signal line, the lines being coupled to the balun, the lines carrying an in-phase and an out-of-phase signal, respectively; a differential gain network coupled to the in-phase and out-of-phase signal lines, the differential gain network adjusting the amplitude of the in-phase and out-of-phase signals; a differential phase shift network coupled to the differential gain network, the differential phase shift network receiving the amplitude adjusted in-phase and out-of-phase signals and shifting the signals in phase; a signal combiner coupled to the differential phase shift network for combining the amplitude and phase adjusted in-phase and out-of-phase signals; and a microprocessor coupled to the differential gain network and the differential phase shift network for determining and controlling the amplitude and phase adjustments, wherein the differential gain network comprises: a first and second field effect transistor, the gates of the transistors being respectively coupled to the in-phase and out-of-phase signal lines; a current sensing amplifier coupled to the drains of the transistors; and a digital-to-analog converter coupled to both the microprocessor and the gates of the transistors, and wherein the differential phase shift network comprises: a first and second varactor phase shifter coupled respectively to the drains of the first and second transistors; and a digital-to-analog converter coupled to the microprocessor and the first and second varactors.
Claim 5
Dependent Claim
268 words
In a spectrum analyzer having a single balanced mixer with a balun for mixing a radio frequency in-put signal and a local oscillator input signal to produce an intermediate frequency signal, a circuit for minimizing leakage of the local oscillator signal into intermediate frequency circuitry, the circuit comprising: an in-phase signal line and an out-of-phase signal line, the lines being coupled to the balun, the lines carrying an in-phase and an out-of-phase signal, respectively; a differential gain network coupled to the in-phase and out-of-phase signal lines, the differential gain network adjusting the amplitude of the in-phase and out-of-phase signals; a differential phase shift network coupled to the differential gain network, the differential phase shift network receiving the amplitude adjusted in-phase and out-of-phase signals and shifting the signals in phase; a signal combiner coupled to the differential phase shift network for combining the amplitude and phase adjusted in-phase and out-of-phase signals; and a microprocessor coupled to the differential gain network and the differential phase shift network for determining and controlling the amplitude and phase adjustments, wherein the differential gain network comprises: a first and second field effect transistor, the gates of the transistors being respectively coupled to the in-phase and out-of-phase signal lines; a current sensing amplifier coupled to the drains of the transistors; and a digital-to-analog converter coupled to both the microprocessor and the gates of the transistors, and wherein the differential phase shift network comprises: a first and second varactor phase shifter coupled respectively to the drains of the first and second transistors; and a digital-to-analog converter coupled to the microprocessor and the first and second varactors.
Claim 6
Independent Claim
106 words
An apparatus for minimizing local oscillator signal leakage and second order distortion products generated by a mixer, the mixer having an in-phase signal output and an out-of-phase signal output, the apparatus comprising: a microprocessor controlled phase shift network coupled to the in-phase signal output and the out-of-phase signal output for differentially adjusting the phase of the in-phase and out-of-phase signals; a microprocessor controlled gain network coupled to microprocessor controlled phase shift network for differentially adjusting the gain of the phase adjusted in-phase and out-of-phase signals; and a combiner coupled to the microprocessor controlled gain network for combining the gain and phase adjusted in-phase and out-of-phase signals.
Claim 7
Independent Claim
106 words
An apparatus for minimizing local oscillator signal leakage and second order distortion products generated by a mixer, the mixer having an in-phase signal output and an out-of-phase signal output, the apparatus comprising: a microprocessor controlled phase shift network coupled to the in-phase signal output and the out-of-phase signal output for differentially adjusting the phase of the in-phase and out-of-phase signals; a microprocessor controlled gain network coupled to microprocessor controlled phase shift network for differentially adjusting the gain of the phase adjusted in-phase and out-of-phase signals; and a combiner coupled to the microprocessor controlled gain network for combining the gain and phase adjusted in-phase and out-of-phase signals.
Claim 8
Independent Claim
162 words
An apparatus for minimizing local oscillator signal leakage and second order distortion products generated by a mixer, the mixer having an in-phase signal output and an out-of-phase signal output, the apparatus comprising: a microprocessor controlled phase shift network coupled to the in-phase signal output and the out-of-phase signal output for differentially adjusting the phase of the in-phase and out-of-phase signals; a microprocessor controlled gain network coupled to the microprocessor controlled phase shift network for differentially adjusting the gain of the phase adjusted in-phase and out-of-phase signals; and a combiner coupled to the microprocessor controlled gain network for combining the gain and phase adjusted in-phase and out-of-phase signals, wherein the microprocessor controlled gain network comprises: a first and second field effect transistor, the gates of the transistors being respectively coupled to the in-phase and out-of-phase signal outputs; a current sensing amplifier coupled to the drains of the transistors; and a digital-to-analog converter coupled to both the microprocessor and the gates of the transistors.
Claim 9
Independent Claim
162 words
An apparatus for minimizing local oscillator signal leakage and second order distortion products generated by a mixer, the mixer having an in-phase signal output and an out-of-phase signal output, the apparatus comprising: a microprocessor controlled phase shift network coupled to the in-phase signal output and the out-of-phase signal output for differentially adjusting the phase of the in-phase and out-of-phase signals; a microprocessor controlled gain network coupled to the microprocessor controlled phase shift network for differentially adjusting the gain of the phase adjusted in-phase and out-of-phase signals; and a combiner coupled to the microprocessor controlled gain network for combining the gain and phase adjusted in-phase and out-of-phase signals, wherein the microprocessor controlled gain network comprises: a first and second field effect transistor, the gates of the transistors being respectively coupled to the in-phase and out-of-phase signal outputs; a current sensing amplifier coupled to the drains of the transistors; and a digital-to-analog converter coupled to both the microprocessor and the gates of the transistors.
Claim 10
Dependent Claim
45 words
The apparatus of claim 5 wherein the microprocessor controlled phase shift network comprises: a first and second varactor phase shifter coupled respectively to the drains of the first and second transistors; and a digital-to-analog converter coupled to the microprocessor and the first and second varactors.
Claim 11
Independent Claim
86 words
A method for minimizing leakage of local oscillator signal into intermediate frequency circuitry, the method comprising the steps of: generating an in-phase and an out-of-phase signal from a mixer combining a local oscillator signal and a radio frequency input signal; adjusting the amplitude of the in-phase and out-of-phase signals in a microprocessor controlled gain network; adjusting the phase of the in-phase and out-of-phase signals in a microprocessor controlled phase shift network; and combining the phase and amplitude adjusted in-phase and out-of-phase signals in a signal combiner.
Claim 12
Independent Claim
86 words
A method for minimizing leakage of local oscillator signal into intermediate frequency circuitry, the method comprising the steps of: generating an in-phase and an out-of-phase signal from a mixer combining a local oscillator signal and a radio frequency input signal; adjusting the amplitude of the in-phase and out-of-phase signals in a microprocessor controlled gain network; adjusting the phase of the in-phase and out-of-phase signals in a microprocessor controlled phase shift network; and combining the phase and amplitude adjusted in-phase and out-of-phase signals in a signal combiner.
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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) | 2002-01-18 | 2002-07-20 | 2003-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-01-18 | 2006-07-20 | 2007-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-01-18 | 2010-07-20 | 2011-01-19 | $7700.00 | Window Closed / Lapsed |