Abstract: A radar warning receiver is provided having a police radar signal band discrimination circuit which generates evaluation signals, the state of which indicates the voltage level relative a threshold voltage of a discriminator output as the local oscillator is swept through the radar bands. The times during which the evaluation signals are in one state or the other are utilized to identify in which band the received signal is operating (e.g., X-band or K-band).

Abstract: A radar warning receiver is provided having a police radar signal detection circuit which generates evaluation signals, the state of which indicates the voltage level relative a threshold voltage of a discriminator output as the local oscillator is swept through the radar band. The times during which the evaluation signals are in one state or the other are utilized to identify whether the received signal is from a fixed frequency (e.g., police radar) source or a variable frequency source (e.g., spurious signals).

Abstract: An improved FM receiver is disclosed incorporating improved oscillating limiter circuitry having an electrically tunable bandpass filter which is phase modulated by the baseband signal the phase of which has been advanced in accordance with the formula: ##EQU1## wherein td.sub.1 equals the time delay through the limiter, td.sub.2 equals the time delay through the feedback filter, td.sub.3 equals the time delay through the demodulator and f.sub.n equals the frequency of the respective baseband components.

Abstract: A compact police radar warning receiver is provided having an antenna in which some of the mixer and oscillator components are secured to the antenna by a cantilever structure formed integral the circuit board overlying a portion of the antenna and to which the components are electrically and mechanically coupled.

Abstract: An improved FM receiver is disclosed incorporating improved oscillating limiter circuitry having an electrically tunable bandpass filter and variable attenuator in regenerative feedback relationship around the limiter. The electrically tunable bandpass filter is responsive to DC components and high frequency noise components of the demodulated video baseband signal. The variable attenuator is responsive to the carrier-to-noise ratio of the received FM signal whereby the amount of regenerative feedback around the limiter will vary inversely proportional to charges in the carrier-to-noise ratio.

Abstract: A radar warning receiver is provided having an alarm indicator responsive to an electronic switch, the switch being activated and energizing the alarm in response to an alarm signal indicating the presence of a police radar signal, the switch being deactivated and de-energizing the alarm in response to a mute signal occurring during the occurrence of the alarm signal, the switch remaining deactivated until the alarm condition signal terminates and subsequently reoccurs.

Abstract: A compact police radar warning receiver is provided having an antenna in which all of the mixer and oscillator components are mounted to one side of the antenna enabling the exterior wall of the side opposite thereto to be constructed substantially flat and thereby function as one of the exterior walls of the housing. The antenna is further provided with an improved microwave oscillator, an impedance transformer and non-adjustably positioned tuning pins.

Abstract: A radar warning receiver is provided including a plug adapted to be received within a vehicle cigarette lighter socket, wherein the plug incorporates a metal plate having (1) a foward end to which is provided a pair of outwardly bowed resilient spring arms which extend exteriorly of the plug to make electrical, physical and thermally conductive contact with the vehicle cigarette lighter socket and, (2) mounted thereto a power regulating device. The thermally conductive contact permits reduction in the size of the gripping end of the plug. Accordingly, the gripping end of the plug is sized to be conveniently gripped between the thumb and fingers of a human hand.

Abstract: A box-shaped metal microwave oscillator is provided having two pairs of substantially parallel, confronting inner surfaces, the second pair perpendicular to the first pair to define an oscillator cavity. The forward end of the cavity is walled off with a slotted wall to permit only a portion of the oscillator energy to be emitted. The spacing of certain of the walls and the location of the oscillator components to the wall is described.

Abstract: A radar warning receiver includes means for distinguishing pulsed or continuous fixed frequency radar signals emanating from a radar transmitter from variable frequency signals such as those radiated from a nearby superhomodyne receiver. This invention includes a superheterodyne receiver having a local oscillator that is repeatedly varied in frequency over a range of frequencies sufficiently large and at a rate fast enough to cause any signals within an input range of frequencies to be detected by a sensitive, limited bandwidth detector. If an input signal is fixed in frequency, that signal will be detected at the same time during successive sweeps of the local oscillator, and a correlated output will be generated; otherwise, an uncorrelated output will be generated. If the number of correlated outputs equal or exceed the uncorrelated outputs detected, then an alarm is provided.

Abstract: A radar receiver for detecting quasi-harmonically related radar signals includes an antenna system (10) having a mixer (15) included therein. One harmonic from a local oscillator (20) mixes with a signal at a first frequency to produce an intermediate frequency, and another harmonic of the local oscillator mixes with an input signal at a second frequency also to produce an intermediate frequency. A second mixer (30) and local oscillator (40) may be provided. A bandwidth limited signal detecting system preferably includes a band pass filter (50), a limiting IF amplifier (55) and a frequency discriminator (60). The frequency of either the first or second local oscillator is repeatedly varied by a sweep generator (35) to insure that the presence of a radar signal will pass through the band pass filter (50) and be detected.