| 摘要 |
PURPOSE: To improve the precision of interpolation by processing the clock circuit part of a digital interpolation circuit with a hardware operated at a high speed and processing a time change coefficient filter part with a software facilitating complicated control. CONSTITUTION: Input data are given to a digital signal processing processor DSP19 at a period of a sampling frequency and to delay elements 111 -11N in the DSP19. Every time data are received, the data are shifted in the elements 111 -11N. On the other hand, a clock device 15 is made up of a counter 16 and a latch 17 in terms of hardware. The counter 16 counts count clocks and is reset for each input sampling period. An interpolation timeτis latched by a latch 17 by reading the count of the counter 1 by the latch 17 for each output sampling period. Letτbe 1, then time change coefficientsαD(1)-αN(1) are read sequentially from a memory 14 and given to a coefficient multiplier 12, in which each coefficient is multiplied with input data and integrated (13, 18) and the result is provided as an output.
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