Voltage controlled oscillator, voltage controlled oscillator device and radar device

• US 20020024396A1
• Filed: 07/17/2001
• Published: 02/28/2002
• Est. Priority Date: 07/24/2000
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Haruta, Kazumasa, Yamashita, Sadao
• Granted Patent: US 6,535,072 B2
• Time in Patent Office: Days
• US Class Current: 331/107SL
• CPC Class Codes: G01S 7/4017 of HF systems
• CPC Class Codes: H03B 5/1864 the frequency-determining element being a dielectric resonator
• CPC Class Codes: H03B 9/14 and elements comprising distributed inductance and capacitance

Abstract

A voltage controlled oscillator, a voltage controlled oscillator device, and a radar device provided therewith which can detect when the oscillation frequency becomes uncontrollable. According to one embodiment, a Gunn or other oscillation device is connected to a main line, and a varactor diode which is a variable reactance element is connected between the main line and a sub line to constitute a voltage controlled oscillator. A control voltage is applied to the varactor diode via a switching circuit, and the presence or absence of oscillation or a failure of the varactor diode or oscillation device is detected by a detection signal, for example, from the varactor diode as monitored by a voltage monitor, and/or from the oscillation device, as monitored by a current sensing device.

Claims

1. A voltage controlled oscillator comprising:

a line;

a variable reactance element connected to the line, directly or indirectly via a resonator;

an oscillation device connected to the line; and

a signal output unit to output a detected signal present at said variable reactance element.

2. The voltage controlled oscillator of claim 1, further comprising:

a signal output unit to output a signal detecting a current flowing in said oscillation device.

3. The voltage controlled oscillator of claim 1, wherein the detected signal comprises one of a voltage signal at said variable reactance element and a current signal through said variable reactance element.

4. The voltage controlled oscillator of claim 1, further comprising a second signal output unit for detecting one of a voltage at said oscillation device and a current through said oscillation device.

5. The voltage controlled oscillator of claim 3, wherein the signal output unit detects a voltage signal at said variable reactance element.

6. The voltage controlled oscillator of claim 4, wherein the second signal output unit detects a current through said oscillation device.

7. The voltage controlled oscillator of claim 5, wherein if the voltage level is above a threshold, a normal oscillation condition is determined and if the voltage level is substantially zero, a failure of the variable reactance element on the oscillation device is determined.

8. The voltage controlled oscillator of claim 6, wherein if the second signal output is substantially zero, it is determined that the oscillation device has failed in an open mode and if the signal output is above a predetermined value, it is determined that the oscillation device has failed in a short circuit mode.

9. The voltage controlled oscillator of claim 1, further comprising:

a pick-up which is coupled to the line having said oscillation device connected thereto;

a detector for detecting a signal provided by said pick-up; and

a second signal output unit to output a detection signal from said detector.

10. The voltage controlled oscillator of claim 9, wherein the detector comprises a diode.

11. The voltage controlled oscillator of claim 1, wherein the oscillator device comprises one of an FET and a Gunn diode.

12. The voltage controlled oscillator of claim 11, wherein the detection signal comprises a voltage level whereby the presence or absence of oscillation of said oscillator device can be determined.

14. The voltage controlled oscillator device of claim 13, further comprising a switching circuit controlled by said control unit for enabling and disabling said voltage controlled oscillator in accordance with the signal output from the signal output unit.

15. The voltage controlled oscillator device of claim 14, further wherein the switching circuit is controlled by said control unit to enable and disable said voltage controlled oscillator in accordance with a signal from the signal output unit detecting a failure in said variable reactance element.

16. The voltage controlled oscillator device of claim 15, further comprising a transmitter/receiver coupled to said voltage controlled oscillator and control unit, the voltage controlled oscillator being controlled by said control unit and providing a modulated RF output signal to the transmitter/receiver, the transmitter/receiver providing a received signal received by an antenna to said control unit for determining the presence of an object.

18. The radar device of claim 17, further comprising a signal output unit to output a signal detecting a current flowing in said oscillation device.

19. The radar device of claim 17, further comprising:

a pick-up which is coupled to the line having said oscillation device connected thereto;

a detector for detecting a signal provided by said pick-up; and

a second signal output unit to output a detection signal from said detector.

20. The radar device of claim 17, further comprising:

an A/D converter for converting the signal outputted from the signal output unit into digital data; and

a control unit for controlling said voltage controlled oscillator in accordance with the digit data output from said A/D converter.

13. A voltage controlled oscillator device comprising:

a voltage controlled oscillator comprising a line;

a variable reactance element connected to the line, directly or indirectly via a resonator;

an oscillation device connected to the line; and

a signal output unit to output a detected signal present at said variable reactance element, further comprising;

an A/D converter for converting the signal outputted from the signal output unit into digital data; and

a control unit for controlling said voltage controlled oscillator in accordance with the digital data output from said A/D converter.

17. A radar device comprising:

a voltage controlled oscillator comprising;

a line;

a variable reactance element connected to the line, directly or indirectly via a resonator;

an oscillation device connected to the line;

a signal output unit to output a detected signal present at said variable reactance element; and

a transceiver for transmitting a signal to a target and for receiving a reflected signal from the target.