TW344917B - Digital filter device having phase adjustment functions - Google Patents

Abstract

A digital filter device having phase adjustment functions, which comprises: a retained signal unit consisting of a set of registers in series; except for the data input terminal of the first register being connected to the data input signal, the data input terminal of the remaining registers being connected to the data output terminal of the previous register; the enable input terminal of each register all being connected to a clock signal having a frequency eight times higher than the signal frequency of the data input; a retained data signal being outputted from the data output terminal of the end register; a digital filter unit connected to the data output terminal of the end register of the retained signal unit and comprising: a wave frequency upper or lower limit counter, the input terminal of which being separately inputted with a data input signal or a retained data signal for carrying out an upper or lower number determination, then outputting an upper or lower number signal; a multi-level half adder, the upper number input terminal of the first level half adder being connected to an upper number signal, the lower number input terminal being connected to a lower number signal; the upper number input terminal of the remaining levels of half adders being connected to the upper number output terminal of the previous level, the lower number input terminal of the remaining levels of half adders being connected to the lower number output terminal of the previous level; the upper and lower output terminals of the terminal half adder being not used; the output terminal of each level of half adders being separately sending out a sample signal of that level; and a signal phase modification unit electrically connected to the digital filter unit for carrying out phase recovery operation of data signals.