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TP3054 TP3057 ‘‘Enhanced’’ Serial Interface CODEC Filter COMBO Family
August 1994
TP3054 TP3057 ‘‘Enhanced’’ Serial Interface CODEC Filter COMBO Family
General Description
The TP3054 TP3057 family consists of m-law and A-law monolithic PCM CODEC filters utilizing the A D and D A conversion architecture shown in Figure 1 and a serial PCM interface The devices are fabricated using National’s advanced double-poly CMOS process (microCMOS)
The encode portion of each device consists of an input gain adjust amplifier an active RC pre-filter which eliminates very high frequency noise prior to entering a switched-capacitor band-pass filter that rejects signals below 200 Hz and above 3400 Hz Also included are auto-zero circuitry and a companding coder which samples the filtered signal and encodes