| 摘要 |
<P>PROBLEM TO BE SOLVED: To allow an LUT (Look-Up Table) to be updated by executing measuring operation of a frequency control voltage of a VCO while carrying out frequency modulation operation, without stopping functions of an FMCW radar device. <P>SOLUTION: A frequency modulation circuit for the FMCW radar device includes: a frequency modulation unit which includes a voltage-controlled oscillator (1) having VF characteristics and generating a VCO output signal, and a D/A conversion circuit (2); a modulation control circuit (10) for controlling the frequency control voltage on the basis of the look-up table in which the VF characteristics are stored; a local signal generation circuit (5); a difference-frequency signal generation circuit (6) which, when a frequency of an IF signal becomes equal to or lower than a specific frequency, outputs the IF signal; and an IF detection circuit (7) for outputting an IF detection signal. The modulation control circuit sets a frequency of a local signal, derives the VF characteristics at a timing of output of the IF detection signal on the basis of the frequency control voltage and setting contents of the frequency for the local signal generation circuit, and updates contents of the look-up table. <P>COPYRIGHT: (C)2012,JPO&INPIT |
