Valentine Research Inc.

Clarence R Groth

Michael D Valentine

Stephen Ray Scholl

Marwan E Nusair

A frequency scheme for a police radar detector enables the K band and the K.sub.a band to be scanned during a single sweep of a local oscillator which drives a mixer at its fundamental operating mode to produce intermediate frequency signals around 5 Ghz. The frequency scheme simultaneously activates two or four frequency conversion paths in the police radar detector. Accordingly, a radar warning alarm can be given upon detection of radar signals in any one of the frequency conversion paths. The ambiguity as to which one of the two or four frequency conversion paths is receiving a detected radar signal is resolved by applying first and second modulation signals to first and second local oscillators, respectively, so that the radar band of the detected radar signal can also be included within the radar warning alarm. The first and second modulation signals are in quadrature to one another and quadrature correlation is used to determine which frequency conversion path is receiving a radar signal.

Police radar detector for sweeping K and K.sub.A radar bands during one

An input stage for a police radar detector includes a single mixer together with at least one preamplifier to detect radar signals in the X, K and K.sub.a bands. A preamplifier may be used on the X band alone, the K band alone, the K.sub.a band alone, the X and K bands or the X, K and K.sub.a bands. The use of these preamplifiers provides better noise figure; however, multiple responses cannot be scanned at the same time in bands utilizing a preamplifier with sufficient selectivity to reduce noise in its respective image bands to tolerable levels so that some or all of the receiver responses are swept independently with the preamplifier or preamplifiers being enabled one at a time as appropriate for each band being scanned. Since more sweep time is required when multiple responses are no longer swept simultaneously, a currently preferred form of the input stage couples the K.sub.a band signals to a single mixer through a preamplifier which permits multiple responses to be swept in the K.sub.a band, or passively for economy, to receive dual responses in the K.sub.a band. Utilizing a novel frequency scheme for a radar detector yields two responses approximately 1.3 Ghz apart that fall within the K.sub.a band so that the K.sub.a band can be swept by tuning the first LO 124 through a 1.3 Ghz range with the two responses covering the 2.6 Ghz required for sweeping the entire K.sub.a band.

Input stage for police radar detector including input signal

An input stage of a police radar detector is configured so that a near end of a mixer is coupled to an antenna for receiving high frequency signals and a far end of the mixer is coupled to the antenna for receiving low frequency signals. A local oscillator and an intermediate frequency amplifier are also coupled to the far end of the mixer. The low frequency signals, X band police radar signals, are coupled to the far end of the mixer through a band rejection filter, which serves as a diplexer, a preamplifier and a first bandpass filter. The local oscillator is coupled to the far end of the mixer through a second bandpass filter and the far end of the mixer is coupled to the intermediate frequency amplifier through a low pass filter. The high frequency signals, K band and K.sub.a band signals, are coupled to the near end of the mixer from the antenna through a high pass filter. The diplexer in combination with the first and second bandpass filters, the low pass filter and the high pass filter passively multiplex the related signals within the input stage of the police radar detector.

Input stage for a police radar detector

A radar detector suppresses nuisance alerts due to detection of a third harmonic of a common LO signal of other radar detectors by detecting a second harmonic of the offending LO signal. If a detected radar signal in the K.sub.a band is of a frequency within a suspect range corresponding to possible third harmonic spurious LO signals, a determination is made as to whether a potential alert blocking signal around the second harmonic of a nominal 11.55 Ghz signal is also present. In the illustrated embodiment, the second harmonic alert blocking signal which is checked has a frequency which is 2/3 the frequency of the detected K.sub.a signal .+-. a guard band of, for example .+-.40 Mhz, and is within a range of frequencies from about 22.813 Ghz to about 23.8 Ghz. If no blocking signal has been detected within about 10 seconds before or within three sweeps after detection of the K.sub.a band signal in the suspect range, the detected K.sub.a band signal is reported. If a blocking signal is detected, the signal strength of the detected K.sub.a band signal is examined relative to the signal strength of the blocking signal. If the K.sub.a band signal strength is greater than a reporting threshold and also is greater than the signal strength of the blocking signal by a minimum threshold, the detected K.sub.a band signal is reported. Otherwise the detected K.sub.a band signal is treated as a nuisance signal generated by a nearby radar detector and suppressed.

Police radar detector including nuisance alert suppression

A police radar signal detector detects and monitors radar signals from up to nine (9) radar sources until a detected radar signal has not been redetected for a given number of detector operations, or spectrum sweeps, or until a detected signal has been displaced by a higher priority radar signal. In the police radar signal detector of the present invention, a user of the detector is advised not only of the presence of detected radar signals, the frequency band of detected radar signals and the relative field strength of the signals but also of the number of different radar signal sources which are transmitting signals toward the user's motor vehicle. The information provided to the user for the frequency band of detected radar signals and the relative field strength of the signals is for the highest priority radar signal detected if more than one signal has been detected and is being monitored by the detector of the present invention. In addition, the directions of radar sources are determined and the user of the detector is advised of the direction or directions, front, side and rear, of origin of radar sources transmitting signals toward the user's motor vehicle. If sources are oriented at more than one direction relative to the user's motor vehicle, an indicator is illuminated to advise the user of all the directions of origin with the indicator for the direction of origin of the highest priority signal being flashed to so advise the user of the detector. Further, since multiple radar signals can be detected, each time a new radar signal is detected, a distinctive memo alarm is activated to alert the user to the presence of a new radar signal source.

Motor vehicle police radar detector for detecting multiple radar sources

A police radar detector detects both the presence of radar signals incident upon a motor vehicle using the detector and also determines the direction of origin of the source of detected radar signals and alerts the operator of the motor vehicle of the presence and source direction of the radar signals. The radar detector includes at least two antennas and preferably three or more antennas with detector circuitry shared among the antennas in a single detector housing. One of the antennas is directed generally toward the front of the motor vehicle and, for a three antenna embodiment, the second and third antennas are directed at angles of generally 120.degree. to the left and 120.degree. to the right of the front of the vehicle. As the police speed radar frequency bands are scanned or swept, each potential radar signal which is detected is processed to determine the direction of origin of the signals. To determine the direction of origin of sensed radar signals, the signals are detected in all antennas with the signal strengths in the different antennas being compared to determine the direction of origin of the signals. It is preferred to identify the direction of the radar source as being to the front of the vehicle, to the rear of the vehicle, to the left side of the vehicle or to the right side of the vehicle.

Police radar detectors for detecting radar signals and determining the

A police radar detector detects both the presence of radar signals incident upon a motor vehicle using the detector and also determines the direction of origin of the source of detected radar signals and signals the operator of the motor vehicle of the presence and source direction of the radar signals. Preferably, the radar detector includes two antennas with shared circuitry in a single housing. One of the antennas is directed generally toward the front of the motor vehicle and the other antenna is directed generally to the rear of the motor vehicle. As the police speed radar frequency bands are scanned or swept, each potential radar signal which is detected is processed to determine the direction of origin of the signals. To determine the direction of origin of incident radar signals, the signals are detected in both antennas with the signal strengths in the two antennas being compared to determine the direction of origin of the signals. It is preferred to identify the direction of the radar source as being to the front of the vehicle, to the rear of the vehicle or to the side of the vehicle. Empirically determined tables assist in the determination of thresholds for use in the detector to determine direction of the source of detected radar signals.

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Cincinnati, OH, United States of America

Clarence R Groth