数据搜索系统,热门电子元器件搜索 |
|
TS34118 数据表(PDF) 18 Page - Taiwan Semiconductor Company, Ltd |
|
TS34118 数据表(HTML) 18 Page - Taiwan Semiconductor Company, Ltd |
18 / 20 page TS34118 18-20 2004/09 rev. B Application Information Dial Tone Detector The threshold for the dial tone detector is internally set at 15mV (10mVrms) below VB (see Figure 5). That threshold can be reduced by connecting a resistor from RXI to ground. The resistor value is calculated from: R = ⎥⎦ ⎤ ⎢⎣ ⎡ −1 ∆V V 10K B Where VB is the voltage at Pin 15, and ∆V is the amount of threshold reduction. By connecting a resistor from Vcc to RXI, the threshold can be increased. The resistor value is calculated from: R = ⎥⎦ ⎤ ⎢⎣ ⎡ − − 1 ∆V V V 10K B CC Where ∆V is the amount of threshold increase. Background Noise Monitors For testing or circuit analysis purposes, the transmit or receive attenuators can be set to the “on” position, by disabling the background noise monitors, and applying a signal so as to activate the level detectors. Grounding the CPR pin will disable the receive background noise monitor, thereby indicating the “presence of speech” to the attenuator control block. Grounding CPT does the same for the transmit path. Additionally, the receive background noise monitor is automatically disabled by the dial tone detector whenever the receive signal exceeds the detector’s threshold. Transmit / Receive Detection Priority Although the TS34118 was designed to have an idle mode such that the attenuators are halfway between their full on and full off positions, the idle mode can be biased towards the transmit or the receive side. With this done, gaining control of the circuit from idle will be easier for that side towards which it is biased since that path will have less attenuation at idle. By connecting a resistor from CT (pin 14) to ground, the circuit will be biased towards the transmit side. The resistor value is calculated from: R = ⎥⎦ ⎤ ⎢⎣ ⎡ −1 ∆V VB R T Where R is the added resistor, RT is the resistor normally between pins 14 and 15 (typically 120Ω), and ∆V is the difference between VB and the voltage at C7 at idle C refer to (Figure 10) By connecting a resistor from CT (pin 14) to Vcc, the circuit will be biased towards the transmit side. The resistor value is calculated from: R = ⎥⎦ ⎤ ⎢⎣ ⎡ − − 1 ∆V V V R B CC T R, RT, and ∆V are the same as above. Switching time will be somewhat affected in each case due to the different voltage excursions required to get to transmit and receive from idle. For practical considerations, the ∆V shift should not exceed 100mV. |
类似零件编号 - TS34118 |
|
类似说明 - TS34118 |
|
|
链接网址 |
隐私政策 |
ALLDATASHEETCN.COM |
ALLDATASHEET是否为您带来帮助? [ DONATE ] |
关于 Alldatasheet | 广告服务 | 联系我们 | 隐私政策 | 链接交换 | 制造商名单 All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |