| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect abnormality of a word clock to generate an alarm with a simple configuration in a musical sound synthesizer such as a sound source board which operates synchronously with a word clock supplied from outside in every sampling cycle according to a system clock independent of the word clock. <P>SOLUTION: A frequency dividing circuit 62 divides the frequency of a system clock SCLK by two and outputs a signal S1 having a frequency which is 1024 times as high as an ideal sampling frequency Fs. A cycle counter 64 counts this signal S1 and is reset in sampling cycles based upon the word clock WCK. A maximum value of the count value of the cycle counter 64 is stored in an M detection register 52. When the word clock WCK has ideal sampling cycles, the value stored in the M detection register 52 is "1023", but if an error occurs, the value stored in the M detection register 52 is "1023" or below or "1024" and above. <P>COPYRIGHT: (C)2004,JPO |
