Video amplifier for a radar receiver

• US 20030210182A1
• Filed: 08/16/2001
• Published: 11/13/2003
• Est. Priority Date: 08/16/2000
• Status: Active Grant

• Current Assignee: Valeo Radar Systems, Inc. (Valeo SE)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Pleva, Joseph S., Woodington, Walter Gordon, Russell, Mark E., Delcheccolo, Michael Joseph, Van Rees, H. Barteld, Hanson, James T.
• Granted Patent: US 6,903,679 B2
• Time in Patent Office: Days
• US Class Current: 342/175
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60Q 9/008 for anti-collision purposes
• CPC Class Codes: B60T 2201/08 Lane monitoring; Lane Keeping Systems
• CPC Class Codes: B60T 2201/081 using distance control
• CPC Class Codes: B60T 2201/088 using transmission control
• CPC Class Codes: B60W 2530/10 Weight
• CPC Class Codes: B60W 2554/4043 Lateral speed
• CPC Class Codes: B60W 2554/803 Relative lateral speed
• CPC Class Codes: G01S 13/04 Systems determining presence of a target based on relative movement of target G01S13/56
• CPC Class Codes: G01S 13/282 using a frequency modulated carrier wave G01S13/286 takes precedence
• CPC Class Codes: G01S 13/343 using sawtooth modulation
• CPC Class Codes: G01S 13/346 using noise modulation
• CPC Class Codes: G01S 13/48 using multiple beams at emission or reception
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/726 Multiple target tracking
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/0245 Radar with phased array antenna
• CPC Class Codes: G01S 2013/9315 Monitoring blind spots
• CPC Class Codes: G01S 2013/9321 Velocity regulation, e.g. cruise control
• CPC Class Codes: G01S 2013/93271 : in the front of the vehicles
• CPC Class Codes: G01S 2013/93272 : in the back of the vehicles
• CPC Class Codes: G01S 2013/93274 : on the side of the vehicles
• CPC Class Codes: G01S 2013/93275 : in the bumper area
• CPC Class Codes: G01S 7/023 : Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36
• CPC Class Codes: G01S 7/0232 : Avoidance by frequency multiplex
• CPC Class Codes: G01S 7/032 : Constructional details for solid-state radar subsystems
• CPC Class Codes: G01S 7/038 : Feedthrough nulling circuits
• CPC Class Codes: G01S 7/06 : Cathode-ray tube displays or other two dimensional or three-dimensional displays
• CPC Class Codes: G01S 7/288 : Coherent receivers
• CPC Class Codes: G01S 7/352 : Receivers
• CPC Class Codes: G01S 7/354 : Extracting wanted echo-signals Doppler systems G01S13/50
• CPC Class Codes: G01S 7/356 : involving particularities of FFT processing
• CPC Class Codes: G01S 7/4004 : of parts of a radar system
• CPC Class Codes: G01S 7/4008 : of transmitters
• CPC Class Codes: G01S 7/4021 : of receivers
• CPC Class Codes: H01Q 1/3233 : particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems
• CPC Class Codes: H01Q 1/3258 : using the gutter of the vehicle; Means for clamping a whip aerial on the edge of a part of the vehicle
• CPC Class Codes: H01Q 1/3283 : side-mounted antennas, e.g. bumper-mounted, door-mounted mounted on windscreens H01Q1/1271
• CPC Class Codes: H01Q 1/38 : formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 1/42 : Housings not intimately mechanically associated with radiating elements, e.g. radome
• CPC Class Codes: H01Q 13/10 : Resonant slot antennas
• CPC Class Codes: H01Q 13/18 : the slot being backed by, or formed in boundary wall of, a resonant cavity longitudinally slotted cylinder H01Q13/12 ; Open cavity antennas
• CPC Class Codes: H01Q 21/0043 : Slotted waveguides combination with horns H01Q13/0233
• CPC Class Codes: H01Q 21/0075 : Stripline fed arrays H01Q21/065 takes precedence
• CPC Class Codes: H01Q 21/0087 : Apparatus or processes specially adapted for manufacturing antenna arrays manufacturing waveguides H01P11/00
• CPC Class Codes: H01Q 21/065 : Patch antenna array
• CPC Class Codes: H01Q 25/00 : Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00
• CPC Class Codes: H01Q 3/24 : varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 3/40 : with phasing matrix

Abstract

A video amplifier for a radar receiver includes a temperature compensating attenuator. The attenuator includes a temperature sensitive device, such as a thermistor, arranged in a voltage divider network and is coupled in cascade between two filter stages. Each of the filter stages has a bandpass characteristic in order to filter low-frequency leakage signals and provide sensitivity control based on frequency and thus range, while also filtering high frequency signals to reduce aliasing.

Claims

1. A video amplifier comprising:

a first filter stage having an input terminal adapted to receive an RF signal and an output terminal;

an attenuator having an input terminal coupled to the output terminal of said first filter stage and an output terminal, said attenuator comprising a temperature sensitive device; and

a second filter stage having an input terminal coupled to the output terminal of the attenuator and an output terminal at which an output signal of said video amplifier is provided.

2. The video amplifier of claim 1 wherein said temperature sensitive device is a thermistor.

3. The video amplifier of claim 1 wherein each of said first filter stage and said second filter stage comprises a Sallen-Key filter.

4. The video amplifier of claim 1 wherein each of said first filter stage and said second filter stage has a low-pass characteristic.

5. The video amplifier of claim 1 wherein each of said first filter stage and said second filter stage has a bandpass characteristic.

6. A radar receiver comprising:

an RF amplifier having an input terminal adapted to receive an RF signal and an output terminal at which an amplified RF signal is provided;

a down-converter having an input terminal coupled to said output terminal of said RF amplifier and an output terminal at which a lower frequency signal is provided; and

a video amplifier having an input terminal coupled to said output terminal of said down-converter and an output terminal at which a filtered signal is provided, wherein said video amplifier comprises a temperature compensating attenuator.

7. The radar receiver of claim 6 wherein said RF amplifier is comprised of GaAs transistors.

8. The radar receiver of claim 6 wherein said attenuator comprises a thermistor.

9. The radar receiver of claim 8 wherein said attenuator further comprises at least one resistor coupled to said thermistor to form a voltage divider.

10. The radar receiver of claim 6 said video amplifier further comprises:

a first filter stage having an input terminal coupled to said output terminal of said down-converter and an output terminal coupled to said temperature compensating attenuator; and

a second filter stage having an input terminal coupled to said temperature compensating attenuator and an output terminal at which said filtered signal is provided.

11. The radar receiver of claim 9 wherein each of said first filter stage and said second filter stage has a bandpass characteristic.

12. The radar receiver of claim 11 wherein said bandpass characteristic has a low frequency cutoff selected to attenuate a leakage signal.

13. The radar receiver of claim 11 wherein said bandpass characteristic has a low frequency cutoff selected to attenuate a received RF signal reflected by an object located more than a predetermined distance from said RF receiver.

14. A radar system comprising:

a transmit antenna for transmitting a first RF signal;

a receive antenna for receiving a second RF signal; and

a receiver circuit coupled to said receive antenna for processing said second RF signal and comprising a temperature compensated video amplifier.

15. The radar system of claim 14 wherein said temperature compensated video amplifier comprises:

a first filter stage having an input terminal adapted to receive said second RF signal and an output terminal

an attenuator having an input terminal coupled to the output terminal of said first filter stage and having an output terminal, said attenuator comprising a temperature sensitive device; and

a second filter stage having an input terminal coupled to the output terminal of the attenuator and an output terminal at which an output signal of said video amplifier is provided.

16. The radar system of claim 15 wherein said receiver circuit further comprises an RF amplifier having a gain which varies by a first predetermined amount with temperature and wherein said attenuator provides a gain which varies by a second predetermined amount with temperature, wherein said first and second predetermined amounts are substantially equal.

17. The radar system of claim 14 wherein each of said first filter stage and said second filter stage has a bandpass characteristic.

18. The radar system of claim 17 wherein said second RF signal includes a portion of said first RF signal and wherein said bandpass characteristic has a low frequency cutoff selected to attenuate said portion of said first RF signal.

19. The radar system of claim 17 wherein said bandpass characteristic has a low frequency cutoff selected to attenuate a received RF signal reflected by an object located more than a predetermined distance from said radar system.

20. The radar system of claim 15 further comprising:

an analog-to-digital converter responsive to said output signal of said video amplifier for providing a digital signal;

a temperature sensor for providing a signal indicative of the temperature of said receiver circuit; and

a digital signal processor responsive to said temperature indicative signal for varying a threshold used to process said digital signal.