US 5,465,418 AGranted

Self-oscillating mixer circuits and methods therefor

AssigneeDrexel University

InventorsXuesong Zhou, Afshin S. Daryoush

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Abstract

Self-oscillating mixer circuits for use in communications systems. The circuits comprise a push-pull amplifier for amplifying a signal having a first frequency to produce an amplified signal, a feedback loop coupled to the push-pull amplifier for phase shifting the amplified signal during each half cycle of the push-pull amplifier, thereby creating an oscillating output signal, and a mixing element for coupling the oscillating output signal to the signal having the first frequency, thereby mixing the signal having the first frequency with the oscillating signal to produce a signal having a second frequency. The circuits described herein have transistors that operate near the class B mode to obtain optimal frequency conversion with minimal power consumption. These circuits will therefore find use in any communications-type system which requires a frequency converter.

Claims7

Dependent claims

A tunable communications circuit for transforming a signal having a first frequency to a signal having a second frequency comprising:

push-pull amplifier means for amplifying the signal having the first frequency to produce an amplified signal, wherein the push-pull amplifier means comprises a pair of field effect transistors;
feedback means coupled to the push-pull amplifier means for phase shifting the amplified signal during each half cycle of the push-pull amplifier means, thereby creating an oscillating output signal, wherein the feedback means comprises at least one transmission line connected between a drain and a gate of one of the field effect transistors such that a substantially one hundred and eighty degree phase shift is introduced to the amplified signal;
means coupled to said push-pull amplifier means for coupling said oscillating output signal to said signal having the first frequency, whereby said push-pull amplifier means mixes the signal having the first frequency with the oscillating signal to produce the signal of the second frequency;
means interfaced with a gate terminal of one of the pair of field effect transistors for locking the frequency of the oscillating signal to prevent the oscillating signal from being free-running;
output means coupled to drain terminals of the pair of field effect transistors for receiving the signal having the second frequency;
and
wherein the transistors operate at Class B for both oscillation and mixing functions and said Class B operation enables simultaneous realization of large locking range and high conversion gain;
and wherein the circuit exhibits phase control of said signals of said first and second frequency.

5 more elements

A self-oscillating mixer circuit for converting a signal having a first frequency to a signal having a second frequency comprising:

first amplifier means for receiving the signal of the first frequency and amplifying the signal of the first frequency during a half cycle of the signal of the first frequency, wherein said first amplifier means comprises a first field effect transistor;
second amplifier means coupled to the first amplifier means for amplifying the signal of the first frequency during an alternate half cycle of the signal of the first frequency, wherein said second amplifier means comprises a second field effect transistor, and wherein said first and second amplifier means are interfaced together to form a push-pull amplifier;
phase shift means coupled to said first and second field effect transistors for shifting an amplified signal output from said first and second amplifier means to cause the amplified signal output to oscillate, thereby producing an oscillating signal, wherein the phase shift means comprises at least one transmission line connected in a feedback loop between a drain and a gate of one of the field effect transistors such that a substantially one hundred and eighty degree phase shift is introduced to the amplified signal;
means coupled to said phase shift means for mixing said oscillating signal with said signal of the first frequency, thereby producing the signal having the second frequency;
means interfaced with a gate terminal of one of the pair of field effect transistors for locking the frequency of the oscillating signal to prevent the oscillating signal from being free-running;
output means coupled to drain terminals of the pair of field effect transistors for receiving the signal having the second frequency;
and
division means coupled to a drain terminal of one of the field the field effect transistors for dividing the oscillating signal into signals corresponding to subharmonic signals of the oscillating signal.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/180,650Filed 13 Jan 1994 · continuation in part
Priority: 29 Apr 1993
Granted: 7 Nov 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H04B 1/28
For superheterodyne receivers: the receiver comprising at least one semiconductor device having three or more electrodes
H03D 7/125
By means of semiconductor devices having more than two electrodes: with field effect transistors
H03D 9/0675
By means of semiconductor devices having more than two electrodes: using field effect transistors
H03B 5/00
Generation of oscillations using amplifier with regenerative feedback from output to input