參數(shù)資料
型號: TCM129C16
廠商: Texas Instruments, Inc.
元件分類: Codec
英文描述: Single-Chip PCM Codecs And Filters(組合編碼譯碼器/濾波器)
中文描述: 單芯片的PCM編解碼器和過濾器(組合編碼譯碼器/濾波器)
文件頁數(shù): 21/25頁
文件大?。?/td> 556K
代理商: TCM129C16
TCM29C13, TCM29C14, TCM29C16, TCM29C17,
TCM129C13, TCM129C14, TCM129C16, TCM129C17
COMBINED SINGLE-CHIP PCM CODEC AND FILTER
SCTS011G – APRIL 1986 – REVISED JULY 1996
21
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PRINCIPLES OF OPERATION
analog loopback
A distinctive feature of the TCM29C14 and TCM129C14 is the analog loopback capability. With this feature, the
user can test the line circuit remotely by comparing the signals sent into the receive channel (PCM IN) with those
generated on the transmit channel (PCM OUT). The test is accomplished by sending a control signal that
internally connects the analog input and output ports. When ANLG LOOP is TTL high, the receive output
(PWRO+) is internally connected to ANLG IN+, GSR is internally connected to PWRO–, and ANLG IN– is
internally connected to GSX (see Figure 9).
_
+
_
+
A/D
D/A
ANLG
IN+
ANLG IN–
GSX
ANLG LOOP
GSR
PCM OUT
Digitized PCM
Loopback
Response
PCM IN
Digitized PCM
Test Tone
Transmit
Voice
PWRO+
PWRO–
Figure 9. TCM129C14 and TCM29C14 Analog Loopback Configuration
Due to the difference in the transmit and receive transmission levels, a 0-dBm0 code into PCM IN emerges from
PCM OUT as a 3-dBm0 code, an implicit gain of 3 dB. Because of this, the maximum signal that can be tested
by analog loopback is 0 dBm0.
precision voltage references
Voltage references that determine the gain dynamic range characteristics of the device are generated internally.
No external components are required to provide the voltage references. A difference in subsurface charge
density between two suitably implanted MOS device is used to derive a temperature- and bias-stable reference
voltage, which is calibrated during the manufacturing process. Separate references are supplied to the transmit
and receive sections, and each is calibrated independently. Each reference value is then further trimmed in the
gain-setting operational amplifiers to a final precision value. Manufacturing tolerances of typically
±
0.04 dB can
be achieved in absolute gain for each half channel, providing the user a significant margin to compensate for
error in other system components.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TCM129C16A 制造商:TI 制造商全稱:Texas Instruments 功能描述:COMBINED SINGLE-CHIP PCM CODEC AND FILTER
TCM129C16ADW 制造商:TI 制造商全稱:Texas Instruments 功能描述:COMBINED SINGLE-CHIP PCM CODEC AND FILTER
TCM129C16AN 制造商:TI 制造商全稱:Texas Instruments 功能描述:COMBINED SINGLE-CHIP PCM CODEC AND FILTER
TCM129C16DW 制造商:Rochester Electronics LLC 功能描述:- Bulk
TCM129C16N 制造商:Rochester Electronics LLC 功能描述:- Bulk