WO1999035510A1

WO1999035510A1 - Multiple-band radar detector

Info

Publication number: WO1999035510A1
Application number: PCT/US1999/000357
Authority: WO
Inventors: David C. Oliva; Philip E. Thistlethwaite; Anthony Mirabelli
Original assignee: Cobra Electronics Corp.
Priority date: 1998-01-07
Filing date: 1999-01-07
Publication date: 1999-07-15
Also published as: AU2107899A

Abstract

A signal detection device (10) for determining presence of one or more of a plurality of predetermined signal frequencies comprising an oscillator (32). The oscillator (32) operates at a separate predetermined frequency and has a means for signal detection (18) and a means (50) for alerting a traveler of the presence of one or more of the plurality of predetermined signal frequencies. The means for signal detection can distinguish between a plurality of different predetermined frequencies.

Description

MULTIPLE-BAND RADAR DETECTOR

DESCRIPTION

Related Applications

This application claims the benefit of U.S. Provisional Application No. 60/070,633, filed January 7, 1998. Technical Field

The present invention relates generally to the detection of speed monitoring signals and traffic warning signals to warn, or otherwise advise, travelers of various speed detection devices and traffic hazards in their particular vicinity. Background Prior Art

Various systems for detecting signals, such as speed monitoring signals, have been available for years . As these devices became more and more prevalent, law enforcement agencies and others took measures to insure against the success of the monitoring devices. One of these measures was to transmit speed detection signals along alternative frequency bands. Thus, previous detectors were rendered obsolete because they were unable to detect the newer signals. Another measure was the development of a radar detector detecting gun. The detecting gun allows others to determine which vehicles are employing radar detection equipment. Recently, radar detectors have been used to warn travelers of real or potential road hazards such as the presence of emergency vehicles or trains. Many conventional speed monitoring devices do not have the capability of distinguishing between signals given off by speed monitoring equipment and signals given off by emergency vehicles or trains.

Since speed monitoring devices are now being operated at different frequencies, and safety warning signals are now present, a device is needed that will detect the different frequencies and warn the traveler accordingly. In addition, devices are needed which are capable of filtering out unwanted noise and thus reliably detecting any relevant signals. The present invention is provided to detect signals along many frequencies and alert the traveler to the traffic situation occurring at that time. Summary of the Invention

It is an object of the invention to provide a radar/laser detector for locating signals along multiple frequency bands. The detector includes a signal detection means, a traffic alert means, and a local oscillator shutdown means and/or a local oscillator frequency shifting means. The detector includes a signal detection means. The signal detection means is capable of detecting signals along multiple predetermined frequency bands. It is contemplated that the detector further comprises a traffic alert means. This traffic alert means includes a visual display, an audible, or both.

In one embodiment, the radar/laser detector comprises a local oscillator shutdown means. This local oscillator shutdown means is activated when the unit detects a radar detector detecting gun. These detecting guns are used by others to determine which travelers are employing speed monitoring device detection equipment. The local oscillator shutdown means will turn the oscillator to a momentary idle mode so that the radar/laser detector will go undetected by a detecting gun. Other features and advantages of the invention will be apparent from the following specification.

Brief Description of the Drawings

FIGURE 1 is a simplified block electrical diagram of an embodiment of a detector in accordance with the present invention.

Detailed Description

While this invention is susceptible of embodiments in many different forms, there will herein be described in detail, preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspects of the invention to the embodiments illustrated. The radar/laser detector of the present invention includes a signal detection means, a traffic alert means, and a local oscillator shutdown means and/or a local oscillator frequency shifting means. The signal detection means is designed to differentiate between signals having multiple predetermined frequencies . The signal detection means is contemplated to identify preferably six bands comprising: X band at 10.525 GHz ± 25 MHz, VG-2 at 11.4 GHz - 11.7 GHz, traffic warning signals at 24.07 GHz, 24.11 GHz, and 24.23 GHz, railroad warning signals at 24.11 and 24.19 GHz, K band at 24.150 GHz ± 100 MHz, Ka band at 33.4 to 36.0 GHz, and lasers at 300 THz to 375 THz .

Referring to FIGURE 1, a block diagram of an embodiment of a multiple signal detector in accordance with the present invention is shown. The detector 10 includes a signal detection means 12 having a plurality of frequency monitor circuits 14j_.__N operably connected between a signal receiver 16 and a detector circuit 18. Each monitor circuit 14_1-N includes a wide band IF amplifier 20 operably connected between an input mixer 22 and an output mixer 24. Connected to the input mixer 22 of each monitor circuit 14₁__N is a preselected local oscillator reference signal 28_!__N and an output from the signal receiver 16. The local oscillator reference signal 28^ is provided by a selectable filter and switch bank 26 receiving from a comb frequency generator 30 a comb of frequencies . The comb frequency generator 30 is responsive to an oscillator signal 31 produced by a master oscillator 32 having a precise frequency and a low level of noise . The comb of frequencies produced by the comb frequency generator 30 in response to oscillator signal 31 include discrete steps δ of a reference frequency f, that is f, f + lδ,f + 2δ, f + 3δ, f + 4δ, ..., etc. Preferably, each step δ is a 500 MHz increment.

Accordingly, the switch 26 is controlled by a select input 58 for passing desired components of the comb of frequencies to the input mixers 22_X._N of the monitor circuits 14₁__N. The input mixer 22 of each monitor circuit 14_X__N provides a difference or intermediate frequency 34 comprising the difference between the output of the signal receiver 16 and the local oscillator reference signal 28. In response to the intermediate frequency 34, the IF amplifier 20 produces an amplified output 36 received by the output mixer 24. In addition, the output mixer 24 receives a swept local oscillator signal 38 from a frequency generator 39. The output mixer 24 provides a difference or intermediate frequency output 40 comprising the difference between amplifier output 36 and the swept local oscillator signal 38.

The outputs 40 of the monitor circuits 14 are received by the detector circuit 18 having a narrow band IF amplifier 42 and one or more detectors 44. The IF amplifier 42 amplifies and passes the outputs 40 to the detectors 48 for determining whether a signal having specific characteristics has been received at signal input 16. If desired, the detectors 48 can check for both input signal characteristics and codes .

The detectors 44 are operably coupled to an alert means 50 having an audible alarm 52 and a visual alarm 54. Accordingly, the detectors 44 enable the alarms upon detection of a speed monitoring signal or traffic warning signal . Also responsive to the output of at least one detector 44 is a control block 56 for disabling the comb frequency generator 30 or, in another embodiment, shifting the frequency outputs of the comb frequency generator 30. In an embodiment, monitor circuit l _λ is configured for identifying X-band signals over a selectable detection frequency range. As stated previously, the switch bank 26 is configured, via select input 58, to assert one of a selectable set of discrete frequencies as local oscillator reference signal 28,. By providing for the selection of discrete frequencies, the frequency range monitored by circuit 14]_. is likewise adjusted for avoiding unwanted or noisy frequencies .

In particular, the local oscillator reference signal 28j has a frequency equal to the center frequency of the desired detection frequency range plus the center frequency of the wide band IF amplifier 20j_.. For example, the reference local oscillator reference signal 28 preferably has a frequency of about 12.500 GHz for a selected detection range of about 10.250 GHz to about 10.750 GHz and IF amplifier 20j_. having a center frequency of 2 GHz (i.e., 2GHz + (10.750GHz + 10.25GHz) /2 ) . The input mixer 22;, provides intermediate signal 34 in response to the selected local oscillator reference input signal 28i and the input signal provided by receiver 16. Preferably, receiver 16 includes a conventional antenna having filters for preventing signals at unwanted frequencies from being passed to the input mixer 22j_.. Further, the antenna can include other filters for preventing outward radiation from the antenna of internally generated radio frequency signals.

The wide band IF amplifier 20j amplifies and passes to the output mixer 24 _{l t} via output path 36j, intermediate frequency signal 34₁ within a bandwidth centered around a preselected center frequency. Preferably, IF amplifier 20_x has a bandwidth of about 500 MHz with a center frequency of about 2 GHz. Output mixer 24_: provides a monitor circuit output 40i in response to the IF amplifier output 36₁ and signal 38_x from local oscillator 39_x that is swept about the same center frequency as provided by IF amplifier 20^

Accordingly, the swept local oscillator 39_: has a center frequency of about 2 GHz and is preferably swept by about +/-250Mhz for ensuring reception of X-band over the entire spectrum of X-band.

The monitor circuit output 40₁ is received, via 10.7 MHz narrow band IF amplifier 42, by detector 44_x for enabling alarms 52 and 54 upon detection of a signal over the detected frequency range.

Turning to monitor circuit 14₂, this portion of the detector 10 is preferably configured for identifying K-band signals over a selectable detection frequency range. Accordingly, switch bank 26 is configured to assert a selected discrete frequency from comb generator 30 as local oscillator reference input signal 28₂. For example, reference signal 28₂ preferably has a frequency of about 26.000 GHz for a selected detection range of about

23.750 GHz to about 24.250 GHz and IF amplifier 20₂ having a center frequency of about 2 GHz. The wide band IF amplifier 20₂ amplifies and passes to output mixer 24₂, via output path 36₂, intermediate frequency signal 34₂ generated by input mixer 22₂ and within a 500 MHz bandwidth centered around the preferred center frequency of about 2 GHz.

Output mixer 24₂ generates monitor circuit output 40₂ in response to the IF amplifier output 36₂ and signal 38₂ from local oscillator 39₂ that is swept by about +/- 250 MHz about the same 2 GHz center frequency as that of wide band IF amplifier 20₂. Accordingly, reception is provided over the entire K-band spectrum. Monitor circuit output 40₂ is received by detector 44₂, via narrow band IF amplifier 42. Upon detection of an appropriate signal over the detected frequency range (e.g., 23.750 GHz to 24.250 GHz), detector 44₂ enables alarms 52 and 54.

In an embodiment, monitor circuit 14_N, for example, can be configured for identifying Ka- band signals within one or more selected signal detection frequency ranges. In particular, switch bank 26 can be configured to provide one or more discrete frequencies from comb generator 30 as reference input 28_N. Preferably, for an IF amplifier 20_N having a center frequency of about 2 GHz, reference input 28₂ provides: 1) a frequency of about

35.000 GHz for a detection frequency range of about 33.250 GHz to about 23.750 GHz; 2) about 36.000 GHz for a detection frequency range of about 33.750 GHz to about 34.250 GHz; 3) about 36.500 GHz for a detection frequency range of about 34.250 GHz to about 34.750 GHz; 4) about 37.000 GHz for a detection frequency range of about 34.750 GHz to about 35.250 GHz; 5) about 37.500 GHz for a detection frequency range of about 35.250 GHz to about 35.750 GHz; and 6) about 38.000 GHz for a detection frequency range of about 35.750 GHz to about 36.250 GHz.

Wide band IF amplifier 20_N passes to output mixer 24_N, via path 36_N, intermediate frequency signal 34_N generated by input mixer 22₂ and having a bandwidth centered around the preferred center frequency of about 2 GHz with about a 500 MHz bandwidth.

Mixer 24₂ generates output 40_N in response to the IF amplifier output 36_N and signal 38_N received from local oscillator 39_N that is swept by about +/- 250 MHz around the matching 2 GHz center frequency of IF amplifier 20₂. Accordingly, reception is provided over the entire Ka-band spectrum.

Monitor circuit output 40_N is received by detector 44₂ wherein alarms 52 and 54 are enabled upon detection of an appropriate signal over the detected frequency range .

In an embodiment, the traffic alert means 50 comprises audible alarm 52, visual alarm 54, or both. The traffic alert means 50 is designed to warn travelers of the presence of a speed monitoring device or a potential or actual traffic hazard. As the signal detection means 12 senses the presence of one of a plurality of predetermined signals, the traffic alert means 50 is activated to notify the traveler that a signal has been received. The traffic alert means can include bell -type alarms or the like and/or light emitting diodes or the like. The traffic alert means can also be used to inform the traveler of the strength of the signal received.

In an embodiment, block 56 can provide a local oscillator shutdown means that is activated when VG-2 frequencies are detected by one of the detection circuits 14. VG-2 frequencies are employed by detecting guns to detect the presence of a radar detector in a traveler's vehicle. This local oscillator shutdown means will momentarily idle the oscillator 32 or frequency generator 30 so that the radar/laser detector will go undetected by the detecting gun.

In the preferred embodiment, when the local oscillator shutdown means and/or the local oscillating shifting means is activated, the traffic alert means is activated via feedback path 60. This function insures that the traveler is warned of the presence of a radar detector detecting gun.

It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.

Claims

C L A I M SWhat is claimed is:

1. A signal detection device for detecting the presence of one or more of a plurality of predetermined signal frequencies, comprising: an oscillator operating at a separate predetermined frequency having means for signal detection and means for alerting a presence of one or more of said plurality of predetermined signal frequencies, wherein the means for signal detection includes a plurality of monitor circuits for detecting a plurality of different frequencies.

2. The signal detection device of claim

1 wherein the monitor circuits are responsive to a plurality of local oscillator reference frequencies selected from a comb of frequencies provided by a comb frequency generator.

3. The signal detection device of claim

2 wherein a switch bank is operably connected between the monitor circuits and the comb frequency generator.

4. The signal detection device of claim 2 wherein the comb of frequencies are about from each other by about 500 MHz.

5. The signal detection device of claim 2 wherein the monitor circuits are responsive to swept local oscillator signals for providing output signals to a detection means.

6. The signal detection device of claim 2 further comprising means for momentarily shutting down the oscillator wherein the means for momentarily shutting down the oscillator is activated when the means for signal detection recognizes the presence of a signal having a frequency between 11.4 GHz to 11.7 GHz.

7. The signal detection device of claim 2 wherein the plurality of predetermined signals comprises K band, K-alpha band, X band VG-2 band, laser band, and a traffic warning band having a traffic warning frequency of 24.07 GHz, 24.11 GHz, or 24.19 GHz.

8. The signal detection device of claim 2 wherein the means for alerting the presence of said signal comprises an audible alarm.

9. The signal detection device of claim 2 wherein the means for alerting the presence of said signal comprises a visual alarm.

10. The signal detection device of claim 2 wherein the means for alerting the presence of said signal comprises an audible alarm and a visual alarm.