Table 2.

Frequency and filter characteristics for each audio quality

Codec	Frequency range (kHz)	Sampling rate	Fp (Hz)a	Fs (Hz)b	Ap (dB)c	As (dB)d
PSTNe codec G.711	0.1–3.4	8 kHz G.711 A-Law	3900	4400	1	60
iPCMwb codec	0.1–8	16 kHz PCMf	8000	8500	1	60
CD low-pass filtered	0.1–8	16 kHz PCM	8000	8500	1	60

^a Frequency at the edge of the pass band.

^b Frequency at the beginning of the stop band.

^c Amount of ripple allowed in the pass-band (also called Apass).

^d Stop-band attenuation.

^e Public switched telephone network.

^f Pulse code modulation.