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| AN84 DIGITAL H Y B R I D W I T H T H E Si305X DAAS 1. Introduction This application note is a guide to understanding and implementing the digital hybrid feature found in Si305x DAA products. The Si305x contains an on-chip analog hybrid that performs the 2- to 4-wire conversion and near-end echo cancellation. This hybrid circuit is adjusted for each ac termination setting selected to achieve a minimum transhybrid balance of 20 dB. The Si305x also offers a digital filter for additional near-end echo cancellation to compensate for any line impedance mismatch. For each ac termination setting, the eight programmable hybrid registers (Registers 4552) can be programmed with coefficients to increase the cancellation under real-world line conditions. This digital filter can produce 10 dB or greater of near-end echo cancellation in addition to the 20 dB from the analog hybrid circuitry. Z-4 Z-1 b0 b1 Z-1 + Z-1 b7 Figure 1. Digital Hybrid Structure Figure 2 illustrates the basic signal flow of the DAA. The digital signal has been upsampled to 16 kHz at the digital hybrid stage. The transmit signal goes through a digital filter, digital-to-analog converter, and analog filter before going out on the line or being used in the analog hybrid circuitry. After the analog hybrid, the receive signal passes through an analog filter, analog-to-digital converter, and digital filter before going back into the digital hybrid. The analog hybrid path adds approximately four samples of delay to the signal. The digital hybrid structure matches this filter delay by delaying the digital samples by the same amount. 1.1. Digital Hybrid Overview Figure 1 describes the basic architecture of the digital hybrid. It is composed of an 8-tap FIR filter. "b0" through "b7" represent the filter coefficients in 2s complement form. The initial 4-sample bulk delay is used to compensate for the round trip delay through the lineside device. This architecture is designed to delay and filter the transmit signal to match the portion not cancelled by the analog hybrid. TX Digital Filters DAC Analog Filters AC Termination Line Driver Line RX Digital Hybrid @16kHz Digital Filters ADC Analog Filters Analog Hybrid Figure 2. Signal Flow Diagram Rev. 0.6 6/07 Copyright (c) 2007 by Silicon Laboratories AN84 AN84 TX HD(ej) at 16 kHz DAC at 16 kHz HT() HL() + RX + + ADC at 16 kHz HR() Figure 3. Model + + A model of the DAA and the phone line is shown in Figure 3. In an ideal system, the analog hybrid yields perfect cancellation of the near-end echo from the transmit path. A mismatch between the ac termination and the load produces an echo that is not removed by the analog hybrid. To increase the near-end echo cancellation, the digital hybrid must equalize the disparity between the impedance mismatch of the ac termination and the line. From the above model, the echo is equal to: echo = H T ( ) x H L ( ) x H R ( ) - H T ( ) x H R ( ) = HT() x HR( )[ HL( ) - 1 ] Substituting for HL() in the equation results in: ZLine ZLine - ZACT H L - 1 = 2 x --------------------------------- - 1 = --------------------------------ZLine + ZACT ZLine + ZACT If ZLINE and ZACT are matched, the analog hybrid perfectly cancels the transmit signal. Substituting this result into the echo equation yields: ZLine - ZACT echo = H T ( ) x H R ( ) --------------------------------ZLine + ZACT HL() consists of the DAA's ac termination in combination with the impedance of the twisted pair transmission line terminated at the central office (CO) by a reference impedance. Figure 4 shows the analog hybrid circuitry and the HL() model expanded to include the ac termination and line. The model for the HT() and HR() plays a critical role in this calculation. The models are quite complex, and sampled data of the models are necessary to calculate the hybrid coefficients. Contact Silicon Labs to acquire the sampled data of the HT() and HR() models. A group delay, which was not illustrated in the model, must also be taken into consideration. Internal DSP and filters cause this delay. Taking the group delay into account, the echo is equal to: j2 --------------- x gd 16000 2 ZACT echo = H T ( ) x H R ( ) x [ HL ( ) - 1 ]e where gd is the group delay. - + + ZLINE The digital hybrid must cancel the echo by intentionally adding the negative of the echo. The HD() should be: j2 --------------- x gd 16000 Figure 4. HL()-1 Model H D ( ) = - H T ( ) x H R ( ) x [ HL ( ) - 1 ]e 2 Rev. 0.6 AN84 1.2. Digital Hybrid Calculation Tool Silicon Labs has developed a useful graphical user interface tool (shown in Figure 5) that will assist in calculating the coefficients to use with the digital hybrid in the Si305x DAA product family. The tool allows the user to enter the reference termination of the central office (in an R + R||C format) and the model for the phone line between the DAA and the central office. The line can be represented by one of the EIA models, shown in " Appendix C--EIA Line Models" on page 24, or as a specified length of wire. The software then executes the Matlab code found in " Appendix A-- Sample MATLAB Code" on page 7, which graphically shows the expected trans-hybrid response of the digital hybrid and lists the best hybrid coefficients to use given the line characteristics. Three graphs are shown in Figure 6. An echo graph is created by intentionally mismatching the 600 ac termination with the TBR21 mode CO termination. The digital hybrid response is the 8-tap FIR filter response calculated using the sample code found in Appendix A. The cancelled graph is obtained by adding the echo and the digital hybrid response. The digital hybrid response looks very similar to an echo. Figure 7 shows the phase of the echo and the digital hybrid response. The phase of an echo and the digital hybrid have the opposite polarity. Figure 8 compares the rejection in dB with and without the digital hybrid. By properly using the digital hybrid, near-end echo cancellation has increased by approximately 20 dB. To use the Digital Hybrid Calculation Tool, simply enter the ACIM value recommended in Table 13 of the Si3050 datasheet into the ACIM control. This value determines the impedance presented by the DAA to the line. It is governed by the region in which the application will be deployed. Next, enter values for R1 and R2 in ohms and C in farads into the appropriate controls. These values will represent the impedance presented by the central office to the line. This value is also governed by the region in which the application will be deployed. Also, select the line-side device used in the application in the pull-down box. Finally, select the line model to be used that will most closely model the line connecting the DAA to the central office. This is done by either picking a specific EIA line model or by specifying a wire gauge and length. Once this is complete, hitting the "CALCULATE" button will generate the coefficients that provide the best performance. For example, if we assume that an application will be deployed within the U.S., we enter a 0 for the ACIM value. Also, the central office impedance in the US is 900 in series with 2.16 F. To enter this information in the GUI, we enter 900 for R1 and a fairly large value for R2, since it is not present. For this example, the value of 100,000 was used. For the C value, we enter 2.16e-6 since the expected units are farads. Also, for this example, we use an EIA model of 0. This means essentially no loop length, and the central office impedance is connected directly to the application. Now, the "CALCULATE" button is pressed, and the resulting coefficients, 0xF8, 0xF9, 0x03, 0xFE, 0xFE, 0x00, 0xFE, and 0x00, are generated. Rev. 0.6 3 AN84 Figure 5. Digital Hybrid 4 Rev. 0.6 AN84 1.3. Conclusion The Si305x DAA product family is designed to increase the near-echo cancellation with an additional hybrid in the digital path operating at 16 kHz. Near-end echo is primarily caused by the mismatch between the ac termination and the CO termination. The transmit and receive signal path also affects the echo to a lesser extent. By introducing a filter that models the near-end echo 180 degrees out-of-phase to the receive path echo, the hybrid response can be improved. This improvement in the hybrid response results in greater cancellation of the transmit signal when the near-end echo and digital hybrid response are added together at the digital hybrid stage. To generate the coefficients, the 8-tap FIR filter structure used in the digital hybrid must be taken into account. This digital filter structure requires the hybrid response to be represented in the z-domain. "Appendix A--Sample MATLAB Code" contains sample MATLAB code to calculate the hybrid coefficients. This code should help in understanding the process of calculating the hybrid coefficients. A hybrid coefficient lookup table can be found in " Appendix B--Hybrid Coefficient Lookup Tables" on page 10. These tables provide a set of coefficients to use for different line conditions. Figure 6. Echo Rev. 0.6 5 AN84 Figure 7. Echo Phase Figure 8. Rejection 6 Rev. 0.6 AN84 APPENDIX A--SAMPLE MATLAB CODE A sample MATLAB program for use in setting the hybrid coefficients is shown below. The code takes the ACIM (Register 30) setting and line model as an input and outputs the best coefficient for the digital hybrid to match the line. function hdh HrPhase); = dig_hybrid(ACIM, R1line, R2line, Cline, HtMag, HtPhase, HrMag, % hdh = dig_hybrid(ACIM, R1line, R2line, Cline, HtMag, HtPhase, HrMag, HrPhase); % % This function calculates the coefficient values for the digital % hybrid given a R1+R2||C model for the line. % % ACIM : register setting of the AC termination % R1line : line R1 % R2line : line R2 % Cline : line C % HtMag : Transmit path response % HtPhase : Transmit path response % HrMag : Receive path response % HrPhase : Receive path response % % hdh : digital hybrid coefficients Nact=ACIM+1; if(R1line==0), R1line=eps; end if(R2line==0), R2line=eps; end if(Cline==0), Cline=eps; end %eps is the smallest value after 0 % Set sample rate and frequency grid fs=16000; f=[eps:1:7999]; w=2*pi*f/fs; %%%%%% Transmit path (Ht) Ht = HtMag .* exp(j*HtPhase) %%%%%%% Receive path (Hr) Hr = HrMag .* exp(j*HrPhase) Rev. 0.6 7 AN84 %%%%%%%%%% Near end echo (H2) % Calculate Zline Zcline=1./(j*2*pi*f*Cline); Zline=R1line + R2line.*Zcline./(R2line+Zcline); % Calculate Zref, assume perfect ACT R1ref=[eps eps 270 220 370 Cref =[eps eps 150 117 310 320 370 275 120 230 110 132 110 350 eps 210 600 1e9 900 1e9 900 1e9 600 270]; 1e9 750]; R2ref=[600 900 750 820 620 1050 820 780 820 1000 900 30 2160 1000 2160 1000 150]*1e-9; Zcact=1./(j*2*pi*f*Cref(Nact)); Zact=R1ref(Nact) + R2ref(Nact).*Zcact./(R2ref(Nact)+Zcact); C9r=0*1e-9; Ycact2=(j*2*pi*f*C9r); Zact=1./(1./Zact + Ycact2); %%%%% HL=2*Zline./(Zact+Zline); HL(1)=0; % Add extra group delay to match measurements gde=-0.225; Hd=-Ht.*Hr.*(HL-1).*exp(j*2*pi/16000*gde*[0:length(Ht)-1]); Hd=[Hd conj(fliplr(Hd))]; % Estimate impulse response to match hd=real(ifft(Hd)); % Truncate coefficients and express in [0 255] hdh=round(hd(5:12)*64); ind=find(hdh<0); hdh(ind)=hdh(ind)+256; echo = Ht.*Hr.*(HL-1).*exp(j*2*pi/16000*gde*[0:length(Ht)-1]); hyb_coef = [0 0 0 0 hd(5:12)]; dig_hyb = freqz(hyb_coef,1,w); figure plot(f,abs(echo),'-',f,abs(dig_hyb),'-.',f,abs(echo+dig_hyb),':') axis([0 4000 0 0.4]) legend('echo','digital hybrid response','cancelled signal') 8 Rev. 0.6 AN84 xlabel('frequency') ylabel('echo') figure plot(f,angle(echo),'-',f,angle(dig_hyb),'-.') axis([0 4000 -pi pi]) legend('echo','digital hybrid response') xlabel('frequency') ylabel('echo') figure plot(f,20*log10(abs(echo)),'-',f,20*log10(abs(echo+dig_hyb)),'-.') axis([0 4000 -42 0]) legend('echo','cancelled signal') xlabel('frequency') ylabel('rejection') Rev. 0.6 9 AN84 APPENDIX B--HYBRID COEFFICIENT LOOKUP TABLES Tables 1-14 (for Rev C and prior versions of the Si3019) and Tables 15-28 (for Rev E and later versions of the Si3019) provide fixed digital hybrid coefficients to best match the line load with specific EIA line models. For this calculation, the EIA line model was incorporated into the HL(w) model. The first column shows which line type was used to calculate the hybrid coefficient. The remaining columns display the hybrid coefficients (Registers 45-52). Table 1. ACIM = 0000 and CO Termination = 900 + 2.16 F Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 248 251 2 5 1 7 4 248 253 252 251 2 249 240 240 239 242 244 244 230 242 240 240 3 3 255 238 235 240 233 228 8 254 254 255 Hybrid Coefficient # 4 254 5 7 7 1 1 6 18 5 5 5 5 254 250 253 252 252 250 7 234 250 250 250 6 0 2 254 254 255 253 247 2 2 2 2 7 254 254 2 2 0 0 1 1 255 254 254 8 0 255 254 254 255 254 253 255 255 255 255 Table 2. ACIM = 0000 and CO Termination = 600 Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 255 2 5 1 7 4 248 2 1 255 2 0 247 243 240 242 244 244 230 250 249 247 3 0 255 241 238 241 234 228 8 254 254 255 Hybrid Coefficient # 4 0 4 8 9 2 2 6 18 4 4 4 5 0 253 253 252 253 251 7 234 253 253 253 6 0 2 255 255 255 254 247 2 1 1 2 7 0 0 2 2 1 1 1 1 0 0 0 8 0 0 254 254 255 254 253 255 0 0 0 10 Rev. 0.6 AN84 Table 3. ACIM = 0000 and CO Termination = 1200 + 376 + 112 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 240 247 2 4 1 7 4 248 249 248 247 2 242 232 238 237 241 244 244 230 233 232 232 3 7 254 234 231 239 233 228 8 253 253 254 Hybrid Coefficient # 4 255 8 6 5 255 0 6 18 8 8 8 5 254 249 253 252 251 249 7 234 249 249 249 6 3 4 254 254 254 252 247 2 3 4 4 7 254 255 2 2 0 0 1 1 255 255 255 8 1 0 254 254 255 253 253 255 0 0 0 Table 4. . ACIM = 0000 and CO Termination = 150 + 510 + 47 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 3 2 3 5 1 7 4 248 4 3 2 2 249 246 244 241 242 244 244 230 248 247 246 3 252 249 240 238 241 234 228 8 246 247 249 Hybrid Coefficient # 4 5 7 5 6 2 2 6 18 7 8 7 5 253 252 254 252 252 251 7 234 253 253 252 6 1 1 255 255 255 253 247 2 0 0 1 7 0 1 2 2 1 1 1 1 1 1 1 8 255 255 255 254 255 254 253 255 255 255 255 Rev. 0.6 11 AN84 Table 5. ACIM = 0000 and CO Termination = 220 + 820 + 150 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 6 3 3 5 1 7 4 248 6 5 3 2 246 246 245 242 242 244 244 230 249 247 246 3 239 241 240 238 241 234 228 8 237 239 241 Hybrid Coefficient # 4 5 2 1 4 2 2 6 18 2 3 2 5 253 254 252 250 251 250 7 234 255 254 254 6 255 255 254 255 254 252 247 2 253 254 255 7 2 1 1 0 0 0 1 1 2 2 1 8 255 255 255 254 254 253 253 255 254 255 255 Table 6. ACIM = 0000 and CO Termination = 600 + 1.5 F Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 255 255 2 5 1 7 4 248 1 0 255 2 254 246 242 240 242 244 244 230 249 247 246 3 254 253 241 237 241 234 228 8 251 252 253 Hybrid Coefficient # 4 254 3 7 8 2 1 6 18 2 3 3 5 254 251 252 252 252 251 7 234 251 251 251 6 254 0 254 254 255 253 247 2 255 0 0 7 254 254 1 1 0 1 1 1 254 254 254 8 254 254 253 253 254 254 253 255 254 254 254 12 Rev. 0.6 AN84 Table 7. ACIM = 0010 and CO Termination = 220 + 120 + 115 nf Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 9 2 255 1 253 4 1 244 6 5 2 2 16 10 0 253 252 253 254 241 15 12 10 3 5 9 3 0 0 249 242 19 6 7 9 Hybrid Coefficient # 4 254 255 2 4 255 255 4 11 254 255 255 5 2 1 0 254 0 254 8 244 3 2 1 6 255 0 1 1 0 255 246 2 255 0 0 7 0 255 0 0 0 0 2 253 0 0 255 8 0 1 0 0 0 255 254 1 0 0 1 Table 8. ACIM = 0011 and CO Termination = 220 + 820 + 115 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 255 255 1 253 4 1 245 1 0 255 2 0 0 0 254 255 0 1 243 2 1 0 3 0 255 253 252 255 249 242 18 252 253 255 Hybrid Coefficient # 4 0 254 252 253 251 252 2 10 255 255 254 5 0 1 255 253 254 253 9 245 1 1 1 6 0 255 254 255 254 253 245 0 254 255 255 7 0 0 255 255 254 254 3 253 1 0 0 8 0 0 0 255 255 254 253 1 255 0 0 Rev. 0.6 13 AN84 Table 9. ACIM = 0100 and CO Termination = 370 + 620 + 310 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 254 255 1 252 3 0 244 1 0 254 2 0 252 248 246 247 248 249 236 255 253 252 3 0 2 253 251 253 246 240 18 255 0 2 Hybrid Coefficient # 4 0 1 4 6 2 3 8 14 0 1 1 5 0 255 253 252 253 252 8 241 255 255 255 6 0 1 0 1 0 255 247 5 0 1 1 7 0 255 0 0 255 255 2 254 0 0 255 8 0 0 255 255 255 254 254 1 0 0 0 Table 10. ACIM = 0100 and CO Termination = 220 + 820 + 120 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 254 255 1 252 3 0 244 1 0 254 2 248 249 249 246 247 248 249 236 251 249 249 3 254 253 251 250 253 246 240 18 249 251 253 Hybrid Coefficient # 4 6 4 2 4 1 2 8 14 5 5 4 5 255 255 254 252 253 252 8 241 0 255 255 6 2 1 0 1 0 254 247 5 0 0 1 7 1 1 0 0 255 255 2 254 2 1 1 8 0 0 0 255 255 254 254 1 255 0 0 14 Rev. 0.6 AN84 Table 11. ACIM = 0101 and CO Termination = 300 + 1000 + 220 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 1 254 255 1 252 3 0 244 1 0 254 2 0 255 252 249 250 251 252 239 1 0 255 3 255 2 0 255 1 251 244 21 254 0 2 Hybrid Coefficient # 4 1 0 2 4 1 2 8 14 255 0 0 5 0 255 254 252 254 253 9 244 1 0 255 6 0 1 0 1 0 255 247 5 255 0 1 7 0 0 255 255 255 255 3 254 0 0 0 8 0 0 255 255 255 254 254 1 0 0 0 Table 12. ACIM = 0101 and CO Termination = 370 + 620 + 310 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 254 255 1 252 3 0 244 1 0 254 2 4 0 252 249 250 251 252 239 3 1 0 3 4 6 1 255 1 250 244 21 3 4 6 Hybrid Coefficient # 4 0 1 3 5 2 3 8 14 0 1 1 5 1 0 254 253 255 254 9 244 1 0 0 6 1 2 1 1 0 255 247 5 0 1 2 7 0 255 0 0 255 255 3 254 0 0 255 8 1 1 0 255 0 255 254 1 0 0 1 Rev. 0.6 15 AN84 Table 13. ACIM = 0101 and CO Termination = 270 + 750 + 150 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 254 255 1 252 3 0 244 1 0 254 2 254 253 252 249 250 251 252 239 0 254 253 3 2 2 0 254 1 250 244 21 255 0 2 Hybrid Coefficient # 4 4 3 2 4 1 2 8 14 3 3 3 5 1 1 255 253 254 253 9 244 2 1 1 6 2 2 1 1 0 255 247 5 0 1 2 7 1 1 0 0 255 255 3 254 1 1 1 8 0 1 0 0 0 255 254 1 0 0 1 Table 14. ACIM = 1010 and CO Termination = 200 + 560 + 100 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 6 4 4 6 2 8 6 249 7 6 4 2 5 4 2 0 0 1 2 244 6 5 4 3 249 247 243 242 244 238 231 8 244 246 247 Hybrid Coefficient # 4 0 255 253 254 251 252 2 12 0 0 255 5 2 2 2 0 0 254 8 245 3 2 2 6 254 253 252 253 252 250 245 252 252 253 253 7 2 2 2 1 1 1 4 0 3 2 2 8 255 255 255 255 255 254 251 1 255 255 255 16 Rev. 0.6 AN84 Table 15. ACIM = 0000 and CO Termination = 900 + 2.16 F Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 248 251 2 5 1 7 4 248 253 252 251 2 249 240 240 239 242 244 244 230 242 240 240 3 3 255 238 235 240 233 228 8 254 254 255 Hybrid Coefficient # 4 254 5 7 7 1 1 6 18 5 5 5 5 254 250 253 252 252 250 7 234 250 250 250 6 0 2 254 254 255 253 247 2 2 2 2 7 254 254 2 2 0 0 1 1 255 254 254 8 0 255 254 254 255 254 253 255 255 255 255 Table 16. ACIM = 0000 and CO Termination = 600 Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 255 2 5 1 7 4 248 2 1 255 2 0 247 243 240 242 244 244 230 250 249 247 3 0 255 241 238 241 234 228 8 254 254 255 Hybrid Coefficient # 4 0 4 8 9 2 2 6 18 4 4 4 5 0 253 253 252 253 251 7 234 253 253 253 6 0 2 255 255 255 254 247 2 1 1 2 7 0 0 2 2 1 1 1 1 0 0 0 8 0 0 254 254 255 254 253 255 0 0 0 Rev. 0.6 17 AN84 Table 17. ACIM = 0000 and CO Termination = 1200 + 376 + 112 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 240 247 2 4 1 7 4 248 249 248 247 2 242 232 238 237 241 244 244 230 233 232 232 3 7 254 234 231 239 233 228 8 253 253 254 Hybrid Coefficient # 4 255 8 6 5 255 0 6 18 8 8 8 5 254 249 253 252 251 249 7 234 249 249 249 6 3 4 254 254 254 252 247 2 3 4 4 7 254 255 2 2 0 0 1 1 255 255 255 8 1 0 254 254 255 253 253 255 0 0 0 Table 18. ACIM = 0000 and CO Termination = 150 + 510 + 47 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 3 2 3 5 1 7 4 248 4 3 2 2 249 246 244 241 242 244 244 230 248 247 246 3 252 249 240 238 241 234 228 8 246 247 249 Hybrid Coefficient # 4 5 7 5 6 2 2 6 18 7 8 7 5 253 252 254 252 252 251 7 234 253 253 252 6 1 1 255 255 255 253 247 2 0 0 1 7 0 1 2 2 1 1 1 1 1 1 1 8 255 255 255 254 255 254 253 255 255 255 255 18 Rev. 0.6 AN84 Table 19. ACIM = 0000 and CO Termination = 220 + 820 + 150 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 6 3 3 5 1 7 4 248 6 5 3 2 246 246 245 242 242 244 244 230 249 247 246 3 239 241 240 238 241 234 228 8 237 239 241 Hybrid Coefficient # 4 5 2 1 4 2 2 6 18 2 3 2 5 253 254 252 250 251 250 7 234 255 254 254 6 255 255 254 255 254 252 247 2 253 254 255 7 2 1 1 0 0 0 1 1 2 2 1 8 255 255 255 254 254 253 253 255 254 255 255 Table 20. ACIM = 0000 and CO Termination = 600 + 1.5 F Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 255 255 2 5 1 7 4 248 1 0 255 2 254 246 242 240 242 244 244 230 249 247 246 3 254 253 241 237 241 234 228 8 251 252 253 Hybrid Coefficient # 4 254 3 7 8 2 1 6 18 2 3 3 5 254 251 252 252 252 251 7 234 251 251 251 6 254 0 254 254 255 253 247 2 255 0 0 7 254 254 1 1 0 1 1 1 254 254 254 8 254 254 253 253 254 254 253 255 254 254 254 Rev. 0.6 19 AN84 Table 21. ACIM = 0010 and CO Termination = 220 + 120 + 115 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 9 2 255 1 253 4 1 244 6 5 2 2 16 10 0 253 252 253 254 241 15 12 10 3 5 9 3 0 0 249 242 19 6 7 9 Hybrid Coefficient # 4 254 255 2 4 255 255 4 11 254 255 255 5 2 1 0 254 0 254 8 244 3 2 1 6 255 0 1 1 0 255 246 2 255 0 0 7 0 255 0 0 0 0 2 253 0 0 255 8 0 1 0 0 0 255 254 1 0 0 1 Table 22. ACIM = 0011 and CO Termination = 220 + 820 + 115 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 255 255 1 253 4 1 245 1 0 255 2 0 0 0 254 255 0 1 243 2 1 0 3 0 255 253 252 255 249 242 18 252 253 255 Hybrid Coefficient # 4 0 254 252 253 251 252 2 10 255 255 254 5 0 1 255 253 254 253 9 245 1 1 1 6 0 255 254 255 254 253 245 0 254 255 255 7 0 0 255 255 254 254 3 253 1 0 0 8 0 0 0 255 255 254 253 1 255 0 0 20 Rev. 0.6 AN84 Table 23. ACIM = 0100 and CO Termination = 370 + 620 + 310 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 254 255 1 252 3 0 244 1 0 254 2 0 252 248 246 247 248 249 236 255 253 252 3 0 2 253 251 253 246 240 18 255 0 2 Hybrid Coefficient # 4 0 1 4 6 2 3 8 14 0 1 1 5 0 255 253 252 253 252 8 241 255 255 255 6 0 1 0 1 0 255 247 5 0 1 1 7 0 255 0 0 255 255 2 254 0 0 255 8 0 0 255 255 255 254 254 1 0 0 0 Table 24. ACIM = 0100 and CO Termination = 220 + 820 + 120 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 254 255 1 252 3 0 244 1 0 254 2 248 249 249 246 247 248 249 236 251 249 249 3 254 253 251 250 253 246 240 18 249 251 253 Hybrid Coefficient # 4 6 4 2 4 1 2 8 14 5 5 4 5 255 255 254 252 253 252 8 241 0 255 255 6 2 1 0 1 0 254 247 5 0 0 1 7 1 1 0 0 255 255 2 254 2 1 1 8 0 0 0 255 255 254 254 1 255 0 0 Rev. 0.6 21 AN84 Table 25. ACIM = 0101 and CO Termination = 300 + 1000 + 220 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 1 254 255 1 252 3 0 244 1 0 254 2 0 255 252 249 250 251 252 239 1 0 255 3 255 2 0 255 1 251 244 21 254 0 2 Hybrid Coefficient # 4 1 0 2 4 1 2 8 14 255 0 0 5 0 255 254 252 254 253 9 244 1 0 255 6 0 1 0 1 0 255 247 5 255 0 1 7 0 0 255 255 255 255 3 254 0 0 0 8 0 0 255 255 255 254 254 1 0 0 0 Table 26. ACIM = 0101 and CO Termination = 370 + 620 + 310 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 254 255 1 252 3 0 244 1 0 254 2 4 0 252 249 250 251 252 239 3 1 0 3 4 6 1 255 1 250 244 21 3 4 6 Hybrid Coefficient # 4 0 1 3 5 2 3 8 14 0 1 1 5 1 0 254 253 255 254 9 244 1 0 0 6 1 2 1 1 0 255 247 5 0 1 2 7 0 255 0 0 255 255 3 254 0 0 255 8 1 1 0 255 0 255 254 1 0 0 1 22 Rev. 0.6 AN84 Table 27. ACIM = 0101 and CO Termination = 270 + 750 + 150 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 0 254 255 1 252 3 0 244 1 0 254 2 254 253 252 249 250 251 252 239 0 254 253 3 2 2 0 254 1 250 244 21 255 0 2 Hybrid Coefficient # 4 4 3 2 4 1 2 8 14 3 3 3 5 1 1 255 253 254 253 9 244 2 1 1 6 2 2 1 1 0 255 247 5 0 1 2 7 1 1 0 0 255 255 3 254 1 1 1 8 0 1 0 0 0 255 254 1 0 0 1 Table 28. ACIM = 1010 and CO Termination = 200 + 560 + 100 nF Line Type 1 EIA 0 EIA 1 EIA 2 EIA 3 EIA 4 EIA 5 EIA 6 EIA 7 2000 ft. 22 awg 2000 ft. 24 awg 2000 ft 26 awg 1 255 255 1 253 3 1 244 2 1 255 2 2 1 255 253 253 254 255 242 4 2 1 3 1 0 252 250 253 246 239 16 253 254 0 Hybrid Coefficient # 4 0 255 252 254 251 252 1 9 255 255 255 5 0 1 0 254 255 253 8 245 2 1 1 6 0 255 255 255 254 253 245 0 254 255 255 7 0 0 0 0 255 255 3 254 1 1 0 8 0 0 0 0 0 254 253 1 0 0 0 Rev. 0.6 23 AN84 APPENDIX C--EIA LINE MODELS EIA1 EO 2 kft 26 AWG NI EIA2 EO 4 kft 26 AWG 3 kft 24 AWG 1.5 kft 26 AWG NI EIA3 EO 7 kft 26 AWG NI EIA4 EO 12 kft 26 AWG 1.5 kft 26 AWG NI EIA5 EO 9 kft 24 AWG 6 kft 24 AWG NI EIA6 EO 3 kft 24 AWG 3 kft 24 AWG 88 6 kft 24 AWG 6 kft 24 AWG 88 6 kft 24 AWG 6 kft 24 AWG 88 6 kft 22 AWG 6 kft 22 AWG 88 9 kft 22 AWG 6 kft 22 AWG 3 kft 22 AWG NI EIA7 EO NI 88 88 88 88 88 Figure 9. EIA Line Models 24 Rev. 0.6 AN84 DOCUMENT CHANGE LIST Revision 0.3 to Revision 0.4 Added Figure 5 on page 4. Added " Appendix C--EIA Line Models" on page 24. Revision 0.4 to Revision 0.5 Updated Figure 5 on page 4. Added Tables 17-32 (information for Rev E and later versions of the Si3019). Revision 0.5 to Revision 0.6 Updated "1.2. Digital Hybrid Calculation Tool" on page 3. Updated Figure 5 on page 4. Updated " Appendix B--Hybrid Coefficient Lookup Tables" on page 10. Rev. 0.6 25 AN84 CONTACT INFORMATION Silicon Laboratories Inc. 400 West Cesar Chavez Austin, TX 78701 Tel: 1+(512) 416-8500 Fax: 1+(512) 416-9669 Toll Free: 1+(877) 444-3032 Email: SiDAAinfo@silabs.com Internet: www.silabs.com The information in this document is believed to be accurate in all respects at the time of publication but is subject to change without notice. Silicon Laboratories assumes no responsibility for errors and omissions, and disclaims responsibility for any consequences resulting from the use of information included herein. Additionally, Silicon Laboratories assumes no responsibility for the functioning of undescribed features or parameters. Silicon Laboratories reserves the right to make changes without further notice. Silicon Laboratories makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Silicon Laboratories assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. Silicon Laboratories products are not designed, intended, or authorized for use in applications intended to support or sustain life, or for any other application in which the failure of the Silicon Laboratories product could create a situation where personal injury or death may occur. Should Buyer purchase or use Silicon Laboratories products for any such unintended or unauthorized application, Buyer shall indemnify and hold Silicon Laboratories harmless against all claims and damages. Silicon Laboratories, Silicon Labs, and ISOmodem are trademarks of Silicon Laboratories Inc. Other products or brandnames mentioned herein are trademarks or registered trademarks of their respective holders. 26 Rev. 0.6 |
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