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What is the condition for a digital filter to be casual?
State the condition for a digital filter to be causal and stable? Ans: A digital filter is causal if its impulse response h (n) =0 for n<0. A digital filter is stable if its impulse response is absolutely summable.
Which filter has more transition band?
The transition bandwidth of a filter largely depends on the order of the filter. For a higher order filter, the transition bandwidth is narrower than for a lower order filter. This is due to the fact that roll-off is higher for a filter of higher order.
Why does a digital filter introduce thermal noise?
A digital filter will introduce noise to a signal during analog low pass filtering, analog to digital conversion, digital to analog conversion and may introduce digital noise due to quantization. With analog filters, every component is a source of thermal noise (such as Johnson noise), so as the filter complexity grows, so does the noise.
How is the transfer function of a digital filter expressed?
The transfer function for a linear, time-invariant, digital filter can be expressed as a transfer function in the Z-domain; if it is causal, then it has the form: where the order of the filter is the greater of N or M. See Z-transform’s LCCD equation for further discussion of this transfer function.
Why are digital filters more expensive than analog filters?
Digital filters may be more expensive than an equivalent analog filter due to their increased complexity, but they make practical many designs that are impractical or impossible as analog filters. Digital filters can often be made very high order, and are often finite impulse response filters which allows for linear phase response.
How is a digital filter implemented in discrete time?
In discrete-time systems, the digital filter is often implemented by converting the transfer function to a linear constant-coefficient difference equation (LCCD) via the Z-transform. The discrete frequency-domain transfer function is written as the ratio of two polynomials.