| 摘要 |
A digitally controlled oscillator is provided with a memory, storing the half periods Ti(i=1, 2, ..., n) of corresponding frequencies fi=1/(2Ti) to be generated, and with a digital feedback circuit, in which circuit the half periods taken from memory are decreased by a fixed time value tau on a time sharing basis, and in which circuit, as soon as the residual values DELTA i,1=Ti-ki,1 tau < tau are obtained, these residual values are increased by the corresponding half periods Ti also on a time sharing basis, and each value so increased is repeatedly decreased by the fixed time tau . On repeating this process j times, the residual values can be expressed by: DELTA i,j=Ti+ DELTA i,j-1-ki,j tau , where each ki,j is so large that 0</= DELTA i,j< tau . The digital feedback circuit is connected to n residual value counters, which are each supplied with a series of residual values DELTA i,j and which, on reaching a fixed value, bring about that a circuit connected to the respective counter produces a square-wave signal of frequency fi. |
