| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of components such as an expensive crystal resonator, and also to reduce a cost and a mounting area in an FM transmitter. SOLUTION: The FM transmitter is provided with: an oscillation circuit of an FM broadcast wave; a stereo modulation circuit for performing stereo modulation for sound signals of two systems on right and left, and outputting a signal for controlling oscillation of the oscillation circuit; and a PLL frequency synthesizer consisting of a program counter for variably dividing the output frequency of the oscillation circuit, of a reference frequency dividing circuit for dividing a reference frequency of 7.6 MHz (or a part for integral multiple of this frequency or integer), and of a phase comparing circuit for comparing an output of the program counter with an output of the reference frequency dividing circuit and outputting a signal for controlling oscillation of the oscillation circuit. The stereo modulation circuit uses a clock to be generated from an output of the reference frequency dividing circuit to make stereo modulation. COPYRIGHT: (C)2006,JPO&NCIPI
|
