| 摘要 |
PURPOSE:To periodically count up a ring memory address function for efficiently attaining address generation of a memory for delaying an FIR filter within an optional integer value. CONSTITUTION:The 1st input signal 24 with n-bit length indicating an address of a memory, the 2nd input signal 25 with n-bit length indicating an index value and the 3rd input signal 26 with n-bit length necessary for periodical counting in a certain fixed range are inputted, the 1st and 2nd input signals are mutually added by an adder 16 with n-bit length and the 1st, 2nd and 3rd input signals are mutually added by an adder 17 with n-bit length. Respective added results are mutually compared by a comparator 21 with n-bit length and either one of outputs from the adders 16, 17 is selected, i.e., a carry to be propagated at the time of periodically counting addresses within the fixed range is detected. In the constitution, the fixed range can be periodically counted up by an optional integer value based upon a certain index value. |
