Voltage controlled oscillator, voltage controlled oscillator device and radar device

• US 6,535,072 B2
• Filed: 07/17/2001
• Issued: 03/18/2003
• Est. Priority Date: 07/24/2000
• Status: Expired due to Fees

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Haruta, Kazumasa, Yamashita, Sadao
• Primary Examiner(s): Lam, Tuan T.
• Application Number:
  US09/907,356
• Publication Number:
  US 20020024396A1
• Time in Patent Office: 609 Days
• Field of Search: 331/99, 331/107.G, 331/107.D, 331/107.DL, 331/107.SL, 331/116.R, 331/116.FE, 331/107.T
• US Class Current: 331/107.00G
• 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 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 second 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 to detect 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 when the voltage level is above a threshold, a normal oscillation condition is determined and when 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 when the second signal output is substantially zero, it is determined that the oscillation device has failed in an open mode and when 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, wherein the oscillator device comprises one of an FET and a Gunn diode.

10. The voltage controlled oscillator of claim 9, wherein the detection signal comprises a voltage level whereby the presence or absence of oscillation of said oscillator device can be determined.

11. The voltage controlled oscillator of claim 1, wherein the variable reactance element is directly connected to the line via the resonator.

12. The voltage controlled oscillator of claim 1, wherein the variable reactance element is indirectly connected to the line via the resonator.

13. A voltage controlled oscillator comprising:

a line;

a variable reactance element connected to the line;

an oscillation device connected to the line;

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

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 a detection signal from said detector.

14. The voltage controlled oscillator of claim 13, wherein the detector comprises a diode.

15. A voltage controlled oscillator device comprising:

a voltage controlled oscillator comprising;

a line;

a variable reactance element connected to the line 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;

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.

16. The voltage controlled oscillator device of claim 15, 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.

17. The voltage controlled oscillator device of claim 16, 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.

18. The voltage controlled oscillator device of claim 17, 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.

19. The voltage controlled oscillator of claim 15, wherein the variable reactance element is directly connected to the line via the resonator.

20. The voltage controlled oscillator of claim 15, wherein the variable reactance element is indirectly connected to the line via the resonator.

21. A radar device comprising:

a voltage controlled oscillator comprising;

a line;

a variable reactance element connected to the line;

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 coupled to said voltage controlled oscillator has been inserted;

for transmitting a signal to a target and for receiving a reflected signal from the target;

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.

22. The radar device of claim 21, further comprising a second signal output unit to output a signal detecting a current flowing in said oscillation device.

23. The radar device of claim 21, 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.