# US 2017/0285139 A1 · Signal generating circuit

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- Number: US 2017/0285139 A1
- Document ID: US20170285139A1
- Status: Published application
- Kind: A1
- Application number: 15/509,580
- Filed: 2014-10-03
- Published: 2017-10-05
- Earliest claimed: 2014-10-03
- Assignees: Mitsubishi Electric Corporation
- Applicants: Mitsubishi Electric Corporation
- Inventors: Kazuhide HIGUCHI; Nobuhiko ANDO; Koji TSUTSUMI; Hiroyuki MIZUTANI; Morishige HIEDA
- Web page: https://patentgrep.com/patent/US20170285139A1

## CPC

- G01S 7/35: Details of non-pulse systems
- G01S 7/40: Means for monitoring or calibrating
- G01S 7/4008: {of transmitters}
- G01S 13/34: using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
- G01S 13/343: {using sawtooth modulation}
- G01S 13/345: {using triangular modulation}
- H03B 23/00: Generation of oscillations periodically swept over a predetermined frequency range (angle-modulating circuits in general H03C3/00)
- H03L 7/093: using special filtering or amplification characteristics in the loop (H03L7/087 - H03L7/091 take precedence)
- H03L 7/18: using a frequency divider or counter in the loop (H03L7/20, H03L7/22 take precedence)
- H03L 7/191: using at least two different signals from the frequency divider or the counter for determining the time difference (H03L7/193, H03L7/195 take precedence)
- H04B 2001/6912: {using chirp}
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- H03B: GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (generators adapted for electrophonic musical instruments G10H; masers or lasers H01S; generation of oscillations in plasma H05H)
- H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B)
- H04B: TRANSMISSION

## Abstract

A signal generating circuit includes a control voltage setting unit (CVSU) configured to set a control voltage for a chirp signal using voltage-frequency characteristics indicating characteristics of an output frequency versus voltage; a VCO configured to alter the frequency of its output signal by the control voltage; a quadrature demodulator configured to perform quadrature demodulation of the output signal of the VCO to generate an inphase signal and a quadrature signal orthogonal to each other; and a frequency detector configured to detect the frequency of the output signal of the VCO on the basis of the inphase signal and quadrature signal. The CVSU corrects the control voltage by using the voltage-frequency characteristics derived from relationships between the control voltage and the frequency of the output signal of the VCO. The VCO generates the chirp signal based on the control voltage corrected by the CVSU.

## Claims

### Claim at position 1

1: A signal generating circuit comprising:
a control voltage setting unit to set a control voltage by using voltage-frequency characteristics indicating characteristics of an output frequency versus voltage;
a voltage controlled oscillator to alter a frequency of an output signal in response to the control voltage;
a quadrature demodulator to carry out quadrature demodulation of part of the output signal of the voltage controlled oscillator using a local signal generated by a local oscillator, to generate an inphase signal and a quadrature signal which are orthogonal to each other; and
a frequency detector to detect the frequency of the output signal of the voltage controlled oscillator on a basis of the inphase signal and the quadrature signal, wherein
the control voltage setting unit corrects the control voltage by using the voltage-frequency characteristics derived from relationships between the control voltage and the frequency of the output signal of the voltage controlled oscillator, and
the voltage controlled oscillator generates a chirp signal on a basis of the control voltage corrected by the control voltage setting unit.

### Claim at position 2 (depends on 1)

2: The signal generating circuit according to claim 1, further comprising a frequency divider to divide the frequency of the output signal of the voltage controlled oscillator, wherein
the quadrature demodulator carries out quadrature demodulation of the output signal of the voltage controlled oscillator whose frequency is divided by the frequency divider.

### Claim at position 3 (depends on 1)

3: The signal generating circuit according to claim 1, further comprising:
a frequency divider to divide the frequency of the output signal of the voltage controlled oscillator; and
a frequency conversion circuit to alter a frequency of an output signal of the frequency divider, wherein
the quadrature demodulator carries out quadrature demodulation of the output signal of the voltage controlled oscillator whose frequency is converted by the frequency conversion circuit.

### Claim at position 4 (depends on 2)

4: The signal generating circuit according to claim 2, wherein the frequency divider outputs, as a frequency-divided signal, an inphase signal and a quadrature signal which are orthogonal to each other.

### Claim at position 5 (depends on 1)

5: The signal generating circuit according to claim 1, further comprising a phase detector to detect a phase from the inphase signal and the quadrature signal, wherein
the frequency detector detects the frequency of the output signal of the voltage controlled oscillator on a basis of the phase detected by the phase detector.

### Claim at position 6 (depends on 5)

6: The signal generating circuit according to claim 5, wherein the phase detector detects the phase by dividing the quadrature signal by the inphase signal and calculating an arctangent of the division result.

### Claim at position 7 (depends on 5)

7: The signal generating circuit according to claim 5, wherein the frequency detector detects the frequency of the output signal of the voltage controlled oscillator on a basis of the frequency obtained by calculating a time derivative of the phase detected by the phase detector.

### Claim at position 8 (depends on 5)

8: The signal generating circuit according to claim 5, wherein the quadrature demodulator, the phase detector, the frequency detector, and the control voltage setting unit are configured with a micro-controller unit.

### Claim at position 9 (depends on 1)

9: The signal generating circuit according to claim 1, wherein the control voltage setting unit includes a lookup table for storing the voltage-frequency characteristics of the voltage controlled oscillator, and sets the control voltage on a basis of the lookup table.

### Claim at position 10 (depends on 3)

10: The signal generating circuit according to claim 3, wherein the frequency divider outputs, as a frequency-divided signal, an inphase signal and a quadrature signal which are orthogonal to each other.

### Claim at position 11 (depends on 6)

11: The signal generating circuit according to claim 6, wherein the frequency detector detects the frequency of the output signal of the voltage controlled oscillator on a basis of the frequency obtained by calculating a time derivative of the phase detected by the phase detector.

### Claim at position 12 (depends on 6)

12: The signal generating circuit according to claim 6, wherein the quadrature demodulator, the phase detector, the frequency detector, and the control voltage setting unit are configured with a micro-controller unit.

### Claim at position 13 (depends on 7)

13: The signal generating circuit according to claim 7, wherein the quadrature demodulator, the phase detector, the frequency detector, and the control voltage setting unit are configured with a micro-controller unit.