Figure shows the frequency response A_e(e^j?) of a discrete-time FIR system for which the impulse response is

(a) Show that A_e(e^j?) cannot correspond to an FIR filter generated by the parks-McClellan algorithm with passband edge frequency of ?/3, a stopband edge frequency of 2?/3, and an error- weighting function of unity in the passband and stopband. Clearly explain your reasoning. The alternation theorem states that the best approximation is unique.

(b) Based on Figure and the statement that A_e(e^j?) cannot correspond to an optimal filter, what can be concluded about the value of L?

Transcribed Image Text:

hel-n). -L