TCM29C13A Datasheet, PDF (20/25 Pages) Texas Instruments – COMBINED SINGLE-CHIP PCM CODEC AND FILTER

TCM29C13A, TCM29C14A, TCM29C16A, TCM29C17A,
TCM129C13A, TC,129C14A, TCM129C16A, TCM129C17A
COMBINED SINGLE-CHIP PCM CODEC AND FILTER
SCTS030E – AUGUST 1989 – REVISED OCTOBER 1996
PRINCIPLES OF OPERATION
fixed-data-rate timing (see Figure 8)
Fixed-data-rate timing is selected by connecting DCLKR to V_BB and uses master clocks CLKX and CLKR,
frame-synchronizer clocks FSX and FSR, and the output TSX. FSX and FSR are 8-kHz inputs that set the
sampling frequency and distinguish between signaling and nonsignaling frames by their pulse durations. A
frame synchronization pulse one master-clock period long designates a nonsignaling frame, while a
double-length sync pulse enables the signaling function (TCM12914A and TCM29C14A only). Data is
transmitted on PCM OUT on the first eight positive transitions of CLKX following the rising edge of FSX. Data
is received on PCM IN on the first eight falling edges of CLKR following FSR. A digital-to-analog (D/A)
conversion is performed on received digital word, and the resulting analog sample is held on an internal
sample-and-hold capacitor until transferred to the receive filter.
The clock-selection terminal (CLKSEL) is used to select the frequency of CLKX and CLKR (TCM29C13A,
TCM29C14A, TCM129C13A, and TCM129C14A only). The TCM29C13A, TCM29C14A, TCM129C13A, and
TCM129C14A fixed-data-rate mode can operate with frequencies of 1.536 MHz, 1.544 MHz, or 2.048 MHz. The
TCM29C16A, TCM29C17A, TCM129C16A, and TCM129C17A fixed-data-rate mode operates at 2.048 MHz
only.
CLKX
FSX
PCM OUT
TS1X
1 2 3 45 67 8
192 /193 / 256
B1 B2 B3 B4 B5 B6 B7 B8
Other
Time Slots
192/193/256
TS1X
1 2 3 45 67 8
Transmit Signal Frame
B7 B8 SIGX
B1 B2 B3 B4 B5 B6
TSX
SIGX
Don’t Care
Don’t Care
Valid
CLKR
FSR
PCM IN
SIGR
TS1R
1 2 3 45 67 89
192 /193 /256
B1 B2 B3 B4 B5 B6 B7 B8
Other
Time Slots
192 /193 /256
TS1R
1 2 3 45 67 8
Receive Signal Frame
SIGR
B1 B2 B3 B4 B5 B6 B7 B8
Previous Value
Figure 8. Signaling Timing (Fixed-Data Rate Only)
New Value
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