- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383935 > TCM37C14ADW (Texas Instruments, Inc.) PCM COMBO WITH PROGRAMMABLE GAIN CONTROL PDF資料下載
參數(shù)資料
| 型號(hào)： | TCM37C14ADW |
| 廠商： | Texas Instruments, Inc. |
| 英文描述： | PCM COMBO WITH PROGRAMMABLE GAIN CONTROL |
| 中文描述： | 的PCM組合，具有可編程增益控制 |
| 文件頁數(shù)： | 18/23頁 |
| 文件大小： | 351K |
| 代理商： | TCM37C14ADW |
TCM37C14A, TCM37C15A
PCMCOMBO WITH PROGRAMMABLE GAIN CONTROL
SLWS018B – JUNE 1996 – REVISED MAY 1998
18
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PRINCIPLES OF OPERATION
transmit operation
The transmit operation is described in the following paragraphs.
transmit filter
The input section provides gain adjustment in the passband by means of an on-chip uncommitted operational
amplifier. The load impedance to ground (AGND) at the amplifier output must be greater than 10 k
in parallel
with less than 50 pF.
A low-pass antialiasing section is included on the device. This section provides 35-dB attenuation at the
sampling frequency. No external components are required to provide the necessary antialiasing function for the
switched capacitor section of the transmit filter.
The band-pass section provides passband flatness and stopband attenuation that fulfills the AT&T D3/D4
channel bank transmission specification and CCITT recommendation G.712. Device specifications meet or
exceed digital class-5 central office switching systems requirements for input signals greater than –55 dBm0.
A high-pass section configuration was chosen to reject low-frequency noise from 50- and 60-Hz power lines,
17-Hz European electric railroads, ringing frequencies and their harmonics, and other low-frequency noise.
Even with the high rejection at these frequencies, the sharpness of the band edge gives low attenuation at
200 Hz. This feature allows the use of low-cost transformer hybrids without external components to be used
in systems.
encoding
The encoder internally samples the output of the transmit filter and holds each sample on an internal
sample-and-hold capacitor. The encoder performs an A/D conversion on a switched-capacitor array. Digital
data representing the sample is then transmitted on the first eight data clocks bits of the next frame.
The autozero circuit corrects for dc offset on the input signal to the encoder, using the sign-bit-averaging
technique. The sign bit from the encoder output is long-term averaged and subtracted from the input to the
encoder, removing all dc offset from the encoder input waveform.
receive operation
The receive operation is described in the following paragraphs.
decoding
The serial PCM word is received at the PCMIN terminal on the first eight data clock bits of the frame. D/A
conversion is performed and the corresponding analog sample is held on an internal sample-and-hold capacitor.
The sample voltage is then transferred to the receive filter.
receive filter
The receive filter provides passband flatness and stopband rejection that fulfills both the AT&T D3/D4
specification and CCITT recommendation G.712. The filter contains the required compensation for the (sin x)/x
response of such decoders.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| TCM37C15AN | PCM COMBO WITH PROGRAMMABLE GAIN CONTROL |
| TCM38C17 | QComboE FOUR-CHANNEL QUAD PCM COMBO |
| TCM38C17IDL | QComboE FOUR-CHANNEL QUAD PCM COMBO |
| TCM38C17IDLDL | QComboE FOUR-CHANNEL QUAD PCM COMBO |
| TCM38C17 | () |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| TCM37C14AIDW | 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Texas Instruments 功能描述: |
| TCM37C15A | 制造商:TI 制造商全稱:Texas Instruments 功能描述:PCM COMBO WITH PROGRAMMABLE GAIN CONTROL |
| TCM37C15A1N | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| TCM37C15ADW | 制造商:TI 制造商全稱:Texas Instruments 功能描述:PCM COMBO WITH PROGRAMMABLE GAIN CONTROL |
| TCM37C15AIDW | 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Texas Instruments 功能描述: |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。