| 摘要 |
<p>In a variable bit rate clock recovery circuit, a phase difference between an input demodulated signal and a recovered clock signal is detected, the detected phase difference signal is filtered by a loop filter (2) and is then integrated (13), the integrated signal is supplied as an address to first and second ROMs (14, 15), which store data of cosine and sine waves in advance, output data from the first (14) and second (15) ROMs are respectively D/A-converted by first (16) and second (17) D/A converters, an output signal from a variable frequency generator (18) is modulated (20) by using an output from the first D/A converter, a signal obtained by shifting (19) the output signal from the variable frequency signal generator (18) by pi /2 radians is modulated (21) by an output from the second D/A converter, and the respective modulated signals are synthesized (22), thereby obtaining a reference clock signal.</p> |
