US 5,946,609 A · Reduced-radiation radio signal receivers

Abstract

A radio receiver with isolation between an antenna and a regenerative oscillator/detector. The isolation is provided by periodically (at the receiver's quench frequency) uncoupling the antenna from the regenerative oscillator/detector. The receiver preferably includes an antenna, a super-regenerative oscillator/detector, a clock that indicates the quench frequency, a timing circuit coupled to the clock, and a switch coupled to the antenna, to the oscillator/detector, and to the timing circuit. The timing circuit specifies a first part and a second part of each clock period. During the first part of each clock period, the switch at least partially couples the antenna to the oscillator/detector on the nominal reception frequency. During the second part of each clock period, the switch at least partially uncouples these two elements on the nominal reception frequency. The timing circuit determines the first and second parts of each clock period so that the first part corresponds to a phase of sensitivity for the oscillator/detector, and so that the second part corresponds to phases in which oscillations in the oscillator/detector rise in amplitude, and/or have an increased amplitude, and/or decay in amplitude. Thus, the inadvertent emission of electromagnetic radiation from the regenerative oscillator/detector at the nominal reception frequency is attenuated or suppressed at least during the second part of each clock period.

Claims50

Dependent claims

A receiver of radio signals, comprising:

an antenna;
a super-regenerative oscillator/detector;
means for fixing periods composed of blocking/unblocking sequences of said oscillator/detector so as to render said oscillator/detector sensitive to energy received on a nominal reception frequency;
wherein said oscillator/detector exhibits, in each of said periods, a phase of sensitivity followed by a phase of amplitude rise or increased amplitude and then of decay of oscillations of said oscillator/detector;
means for fixing in each period a first part and a second part, coupled to said means for fixing periods, wherein said second part follows said first part, wherein the first part corresponds substantially to the phase of sensitivity of said oscillator/detector, and wherein the second part corresponds substantially to the phase of amplitude rise or increased amplitude and of decay of the oscillations of said oscillator/detector;
and
coupling/uncoupling means linked to the antenna, to said oscillator/detector, and to said means for fixing periods, wherein said coupling/uncoupling means at least partially couple the antenna to the oscillator/detector on the nominal reception frequency during said first part of each of said periods, and wherein said coupling/uncoupling means at least partially uncouple the antenna from the oscillator/detector on the nominal reception frequency during at least said second part of each of said periods, so that the electromagnetic energy apt to be emitted by the receiver on said nominal reception frequency at least during said second part of each of said periods is attenuated or suppressed.

4 more elements

A radio receiver, comprising:

an antenna;
a regenerative oscillator;
a clock that indicates a sequence of periods, wherein each period comprises a blocking sequence and an unblocking sequence;
wherein the oscillator is coupled to the clock and configured so that oscillations in the oscillator are blocked during blocking sequences and so that oscillations in the oscillator are unblocked during unblocking sequences;
wherein the oscillator exhibits, in each of the periods, a phase of sensitivity and a phase of feedback;
a timing circuit coupled to the clock, wherein in each of the periods the timing circuit indicates a first part and a second part, wherein the timing circuit is configured so that the first part of each of the periods corresponds substantially to the phase of sensitivity of the oscillator, and wherein the second part of each of the periods corresponds substantially to the phase of feedback of the oscillator;
and
a controllable coupler coupled to the antenna, to the oscillator, and to the timing circuit, wherein the controllable coupler couples the antenna to the oscillator on a reception frequency during the first part of each of the periods, and wherein the controllable coupler at least partially uncouples the antenna from the oscillator on the reception frequency during at least the second part of each of the periods.

5 more elements

Dependencies are inferred from the claim text.

Reduced-radiation radio signal receivers

Life of this patent

Reduced-radiation radio signal receivers

Life of this patent

Abstract

Claims50