công cụ tìm kiếm bảng dữ liệu linh kiện điện tử |
|
STLC3055N bảng dữ liệu(PDF) 8 Page - STMicroelectronics |
|
STLC3055N bảng dữ liệu(HTML) 8 Page - STMicroelectronics |
8 / 25 page STLC3055N 8/25 the CKTTX pin or at least for all the duration of the TTX pulse (including rising and decay phases). ■ D0: enable the TTX generation circuit and define the TTX pulse duration. These two signals are processed by a dedicated circuitry integrated on chip that generate the metering pulse as an amplitude modulated shaped squarewave (SQTTX) (see fig.7). Both the amplitude and the envelope of the squarewave (SQTTX) can be programmed by means of ex- ternal components. In particular the amplitude is set by the two resistors RLV and the shaping by the ca- pacitor CS. Figure 7. Metering Pulse Generation Circuit. The waveform so generated is then filtered and injected on the line. The low pass filter can be obtained using the integrated buffer OP1 connected between pin FTTX (OP1 non inverting input) and RTTX (OP1 output) (see fig.7) and implementing a "Sallen and Key" configuration. Depending on the external components count it is possible to build an optimised application depending on the distortion level required. In particular harmonic distortion levels equal to 13%, 6% and 3% can be obtained respectively with first, second and third order filters (see fig.7). The circuit showed in the "Application diagram" is related to the simple first order filter. Once the shaped and filtered signal is obtained at RTTX buffer output it is injected on the TIP/RING pins with a +6dB gain or +12dB gain. It should be noted that this is the nominal condition obtained in presence of ideal TTX echo cancellation (obtained via proper setting of RTTX and CTTX). In addition the effective level obtained on the line will depend on the line impedance and the protection re- sistors value. In the typical application (TTX line impedance =200 Ω, RP = 50Ω, and ideal TTX echo cancel- lation) the metering pulse level on the line will be 1.33 or 2.66 times the level applied to the RTTX pin. As already mentioned the metering pulse echo cancellation is obtained by means of two external compo- nents (RTTX and CTTX) that should match the line impedance at the TTX frequency. This simple network has a double effect: ■ Synthesize a low output impedance at the TIP/RING pins at the TTX frequency. ■ Cut the eventual TTX echo that will be transferred from the line to the TX output. CTTX1 CTTX2 CS RLV RLV SQTTX BURST D0 CKTTX SHAPING GENERATOR Square wave pulse metering Sinusoidal wave pulse metering RTTX FTTX Low Pass Filter - + OP1 CFL R1 R2 C2 C1 Required external components vs. filter order. Order CFL R1 C1 R2 C2 THD 1 X 13% 2 XXX X 6% 3 X XXX X 3% |
Số phần tương tự - STLC3055N |
|
Mô tả tương tự - STLC3055N |
|
|
Link URL |
Chính sách bảo mật |
ALLDATASHEET.VN |
Cho đến nay ALLDATASHEET có giúp ích cho doanh nghiệp của bạn hay không? [ DONATE ] |
Alldatasheet là | Quảng cáo | Liên lạc với chúng tôi | Chính sách bảo mật | Trao đổi link | Tìm kiếm theo nhà sản xuất 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 |