资 源 简 介
TP3054-X, TP3057-XExtended Temperature Serial Interface CODEC/FilterCOMBO® FamilyGeneral DescripTIonThe TP3054, TP3057 family consists of μ-law and A-lawmonolithic PCM CODEC/filters uTIlizing the A/D and D/Aconversion architecture shown in Figure 1, and a serial PCMinterface. The devices are fabricated using NaTIonal’s advanceddouble-poly CMOS process (microCMOS).The encode porTIon of each device consists of an input gainadjust amplifier, an active RC pre-filter which eliminates veryhigh frequency noise prior to entering a switched-capacitorband-pass filter that rejects signals below 200 Hz and above3400 Hz. Also included are auto-zero circuitry and a compandingcoder which samples the filtered signal and encodesit in the companded μ-law or A-law PCM format. Thedecode portion of each device consists of an expandingdecoder, which reconstructs the analog signal from the compandedμ-law or A-law code, a low-pass filter which correctsfor the sin x/x response of the decoder output and rejectssignals above 3400 Hz followed by a single-ended poweramplifier capable of driving low impedance loads. The devicesrequire two 1.536 MHz, 1.544 MHz or 2.048 MHztransmit and receive master clocks, which may be asynchronous;transmit and receive bit clocks, which may vary from64 kHz to 2.048 MHz; and transmit and receive frame syncpulses. The timing of the frame sync pulses and PCM data iscompatible with both industry standard formats.
