It can effectively filter out the frequency point of a specific frequency or the frequency other than the frequency point and is a device or circuit that has a signal processing effect. It is equivalent to the "sieve" of frequency.
Its input and output are all digital signals. It is a device that changes the relative proportion of the frequency components contained in the input signal or filters out certain frequency components through a certain calculation relationship.
There are two ways to implement digital filters: one is to use computer software to implement; the other is to use a multiplier, delay unit and adder to design a dedicated digital hardware system.
1. The signal-to-noise ratio is high.
The main noise sources in the digital filter are the circuit noise introduced in the analog circuit before the digital system, and the quantization noise generated during the analog-to-digital conversion process at the input of the digital system.
These noises may be amplified in the operation of the digital system, but if a suitable structure is used when designing the filter, the impact of input noise on system performance can be reduced.
2. High reliability. As long as in the working environment of the digital circuit, the digital filter can work stably and reliably.
3. Digital filters can realize functions that cannot be realized by analog filters, such as precise linear phase and multi-rate processing.
4. High precision. As long as the word length is increased, the digital filter can realize signal processing with arbitrary precision.
5. Great flexibility. The implementation of digital filters is more flexible and can be implemented with computer software or large-scale integrated digital hardware.