AN84 D IGITAL H YBRID WITH THE Si305 X DAA S 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. 1.1. Digital Hybrid Overview Digital Filters Z-1 b1 + Z-1 Z-1 b7 Figure 1. Digital Hybrid Structure 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 b0 Z-4 DAC 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. AC Termination Line Driver Analog Filters Line RX Digital Hybrid @16kHz Digital Filters ADC Analog Filters Analog Hybrid Figure 2. Signal Flow Diagram Rev. 0.6 6/07 Copyright © 2007 by Silicon Laboratories AN84 AN84 DAC at 16 kHz TX HL() HT() HD(ej) at 16 kHz - + + 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. Substituting for HL() in the equation results in: Z Line Z Line – Z ACT H L – 1 = 2 ---------------------------------- – 1 = ---------------------------------Z Line + Z ACT Z Line + Z ACT If ZLINE and ZACT are matched, the analog hybrid perfectly cancels the transmit signal. Substituting this result into the echo equation yields: From the above model, the echo is equal to: Z Line – Z ACT echo = H T H R ---------------------------------Z Line + Z ACT echo = H T H L H R – H T H R = HT HR HL – 1 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. 2 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: ZACT echo = H T H R H L – 1 e j2 -------------- 16000 gd 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: H D = – H T H R H L – 1 e Figure 4. HL()–1 Model 2 Rev. 0.6 j2 --------------- gd 16000 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 µF. 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 270 220 370 350 eps 600 900 900 600 270]; R2ref=[600 900 750 820 620 1050 820 780 820 1000 900 1e9 1e9 1e9 1e9 750]; Cref =[eps eps 150 117 310 320 370 275 120 230 110 132 110 210 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 µF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 248 249 3 254 254 0 254 0 EIA 1 251 240 255 5 250 2 254 255 EIA 2 2 240 238 7 253 254 2 254 EIA 3 5 239 235 7 252 254 2 254 EIA 4 1 242 240 1 252 255 0 255 EIA 5 7 244 233 1 250 253 0 254 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 253 242 254 5 250 2 255 255 2000 ft. 24 awg 252 240 254 5 250 2 254 255 2000 ft 26 awg 251 240 255 5 250 2 254 255 Table 2. ACIM = 0000 and CO Termination = 600 Line Type 10 Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 0 0 0 0 0 0 0 EIA 1 255 247 255 4 253 2 0 0 EIA 2 2 243 241 8 253 255 2 254 EIA 3 5 240 238 9 252 255 2 254 EIA 4 1 242 241 2 253 255 1 255 EIA 5 7 244 234 2 251 254 1 254 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 2 250 254 4 253 1 0 0 2000 ft. 24 awg 1 249 254 4 253 1 0 0 2000 ft 26 awg 255 247 255 4 253 2 0 0 Rev. 0.6 AN84 Table 3. ACIM = 0000 and CO Termination = 1200 + 376 + 112 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 240 242 7 255 254 3 254 1 EIA 1 247 232 254 8 249 4 255 0 EIA 2 2 238 234 6 253 254 2 254 EIA 3 4 237 231 5 252 254 2 254 EIA 4 1 241 239 255 251 254 0 255 EIA 5 7 244 233 0 249 252 0 253 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 249 233 253 8 249 3 255 0 2000 ft. 24 awg 248 232 253 8 249 4 255 0 2000 ft 26 awg 247 232 254 8 249 4 255 0 Table 4. . ACIM = 0000 and CO Termination = 150 + 510 + 47 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 3 249 252 5 253 1 0 255 EIA 1 2 246 249 7 252 1 1 255 EIA 2 3 244 240 5 254 255 2 255 EIA 3 5 241 238 6 252 255 2 254 EIA 4 1 242 241 2 252 255 1 255 EIA 5 7 244 234 2 251 253 1 254 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 4 248 246 7 253 0 1 255 2000 ft. 24 awg 3 247 247 8 253 0 1 255 2000 ft 26 awg 2 246 249 7 252 1 1 255 Rev. 0.6 11 AN84 Table 5. ACIM = 0000 and CO Termination = 220 + 820 + 150 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 6 246 239 5 253 255 2 255 EIA 1 3 246 241 2 254 255 1 255 EIA 2 3 245 240 1 252 254 1 255 EIA 3 5 242 238 4 250 255 0 254 EIA 4 1 242 241 2 251 254 0 254 EIA 5 7 244 234 2 250 252 0 253 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 6 249 237 2 255 253 2 254 2000 ft. 24 awg 5 247 239 3 254 254 2 255 2000 ft 26 awg 3 246 241 2 254 255 1 255 Table 6. ACIM = 0000 and CO Termination = 600 + 1.5 µF Line Type 12 Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 255 254 254 254 254 254 254 254 EIA 1 255 246 253 3 251 0 254 254 EIA 2 2 242 241 7 252 254 1 253 EIA 3 5 240 237 8 252 254 1 253 EIA 4 1 242 241 2 252 255 0 254 EIA 5 7 244 234 1 251 253 1 254 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 1 249 251 2 251 255 254 254 2000 ft. 24 awg 0 247 252 3 251 0 254 254 2000 ft 26 awg 255 246 253 3 251 0 254 254 Rev. 0.6 AN84 Table 7. ACIM = 0010 and CO Termination = 220 + 120 + 115 nf Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 9 16 5 254 2 255 0 0 EIA 1 2 10 9 255 1 0 255 1 EIA 2 255 0 3 2 0 1 0 0 EIA 3 1 253 0 4 254 1 0 0 EIA 4 253 252 0 255 0 0 0 0 EIA 5 4 253 249 255 254 255 0 255 EIA 6 1 254 242 4 8 246 2 254 EIA 7 244 241 19 11 244 2 253 1 2000 ft. 22 awg 6 15 6 254 3 255 0 0 2000 ft. 24 awg 5 12 7 255 2 0 0 0 2000 ft 26 awg 2 10 9 255 1 0 255 1 Table 8. ACIM = 0011 and CO Termination = 220 + 820 + 115 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 0 0 0 0 0 0 0 EIA 1 255 0 255 254 1 255 0 0 EIA 2 255 0 253 252 255 254 255 0 EIA 3 1 254 252 253 253 255 255 255 EIA 4 253 255 255 251 254 254 254 255 EIA 5 4 0 249 252 253 253 254 254 EIA 6 1 1 242 2 9 245 3 253 EIA 7 245 243 18 10 245 0 253 1 2000 ft. 22 awg 1 2 252 255 1 254 1 255 2000 ft. 24 awg 0 1 253 255 1 255 0 0 2000 ft 26 awg 255 0 255 254 1 255 0 0 Rev. 0.6 13 AN84 Table 9. ACIM = 0100 and CO Termination = 370 + 620 + 310 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 0 0 0 0 0 0 0 EIA 1 254 252 2 1 255 1 255 0 EIA 2 255 248 253 4 253 0 0 255 EIA 3 1 246 251 6 252 1 0 255 EIA 4 252 247 253 2 253 0 255 255 EIA 5 3 248 246 3 252 255 255 254 EIA 6 0 249 240 8 8 247 2 254 EIA 7 244 236 18 14 241 5 254 1 2000 ft. 22 awg 1 255 255 0 255 0 0 0 2000 ft. 24 awg 0 253 0 1 255 1 0 0 2000 ft 26 awg 254 252 2 1 255 1 255 0 Table 10. ACIM = 0100 and CO Termination = 220 + 820 + 120 nF Line Type 14 Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 248 254 6 255 2 1 0 EIA 1 254 249 253 4 255 1 1 0 EIA 2 255 249 251 2 254 0 0 0 EIA 3 1 246 250 4 252 1 0 255 EIA 4 252 247 253 1 253 0 255 255 EIA 5 3 248 246 2 252 254 255 254 EIA 6 0 249 240 8 8 247 2 254 EIA 7 244 236 18 14 241 5 254 1 2000 ft. 22 awg 1 251 249 5 0 0 2 255 2000 ft. 24 awg 0 249 251 5 255 0 1 0 2000 ft 26 awg 254 249 253 4 255 1 1 0 Rev. 0.6 AN84 Table 11. ACIM = 0101 and CO Termination = 300 + 1000 + 220 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 1 0 255 1 0 0 0 0 EIA 1 254 255 2 0 255 1 0 0 EIA 2 255 252 0 2 254 0 255 255 EIA 3 1 249 255 4 252 1 255 255 EIA 4 252 250 1 1 254 0 255 255 EIA 5 3 251 251 2 253 255 255 254 EIA 6 0 252 244 8 9 247 3 254 EIA 7 244 239 21 14 244 5 254 1 2000 ft. 22 awg 1 1 254 255 1 255 0 0 2000 ft. 24 awg 0 0 0 0 0 0 0 0 2000 ft 26 awg 254 255 2 0 255 1 0 0 Table 12. ACIM = 0101 and CO Termination = 370 + 620 + 310 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 4 4 0 1 1 0 1 EIA 1 254 0 6 1 0 2 255 1 EIA 2 255 252 1 3 254 1 0 0 EIA 3 1 249 255 5 253 1 0 255 EIA 4 252 250 1 2 255 0 255 0 EIA 5 3 251 250 3 254 255 255 255 EIA 6 0 252 244 8 9 247 3 254 EIA 7 244 239 21 14 244 5 254 1 2000 ft. 22 awg 1 3 3 0 1 0 0 0 2000 ft. 24 awg 0 1 4 1 0 1 0 0 2000 ft 26 awg 254 0 6 1 0 2 255 1 Rev. 0.6 15 AN84 Table 13. ACIM = 0101 and CO Termination = 270 + 750 + 150 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 254 2 4 1 2 1 0 EIA 1 254 253 2 3 1 2 1 1 EIA 2 255 252 0 2 255 1 0 0 EIA 3 1 249 254 4 253 1 0 0 EIA 4 252 250 1 1 254 0 255 0 EIA 5 3 251 250 2 253 255 255 255 EIA 6 0 252 244 8 9 247 3 254 EIA 7 244 239 21 14 244 5 254 1 2000 ft. 22 awg 1 0 255 3 2 0 1 0 2000 ft. 24 awg 0 254 0 3 1 1 1 0 2000 ft 26 awg 254 253 2 3 1 2 1 1 Table 14. ACIM = 1010 and CO Termination = 200 + 560 + 100 nF Line Type 16 Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 6 5 249 0 2 254 2 255 EIA 1 4 4 247 255 2 253 2 255 EIA 2 4 2 243 253 2 252 2 255 EIA 3 6 0 242 254 0 253 1 255 EIA 4 2 0 244 251 0 252 1 255 EIA 5 8 1 238 252 254 250 1 254 EIA 6 6 2 231 2 8 245 4 251 EIA 7 249 244 8 12 245 252 0 1 2000 ft. 22 awg 7 6 244 0 3 252 3 255 2000 ft. 24 awg 6 5 246 0 2 253 2 255 2000 ft 26 awg 4 4 247 255 2 253 2 255 Rev. 0.6 AN84 Table 15. ACIM = 0000 and CO Termination = 900 + 2.16 µF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 248 249 3 254 254 0 254 0 EIA 1 251 240 255 5 250 2 254 255 EIA 2 2 240 238 7 253 254 2 254 EIA 3 5 239 235 7 252 254 2 254 EIA 4 1 242 240 1 252 255 0 255 EIA 5 7 244 233 1 250 253 0 254 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 253 242 254 5 250 2 255 255 2000 ft. 24 awg 252 240 254 5 250 2 254 255 2000 ft 26 awg 251 240 255 5 250 2 254 255 Table 16. ACIM = 0000 and CO Termination = 600 Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 0 0 0 0 0 0 0 EIA 1 255 247 255 4 253 2 0 0 EIA 2 2 243 241 8 253 255 2 254 EIA 3 5 240 238 9 252 255 2 254 EIA 4 1 242 241 2 253 255 1 255 EIA 5 7 244 234 2 251 254 1 254 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 2 250 254 4 253 1 0 0 2000 ft. 24 awg 1 249 254 4 253 1 0 0 2000 ft 26 awg 255 247 255 4 253 2 0 0 Rev. 0.6 17 AN84 Table 17. ACIM = 0000 and CO Termination = 1200 + 376 + 112 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 240 242 7 255 254 3 254 1 EIA 1 247 232 254 8 249 4 255 0 EIA 2 2 238 234 6 253 254 2 254 EIA 3 4 237 231 5 252 254 2 254 EIA 4 1 241 239 255 251 254 0 255 EIA 5 7 244 233 0 249 252 0 253 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 249 233 253 8 249 3 255 0 2000 ft. 24 awg 248 232 253 8 249 4 255 0 2000 ft 26 awg 247 232 254 8 249 4 255 0 Table 18. ACIM = 0000 and CO Termination = 150 + 510 + 47 nF Line Type 18 Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 3 249 252 5 253 1 0 255 EIA 1 2 246 249 7 252 1 1 255 EIA 2 3 244 240 5 254 255 2 255 EIA 3 5 241 238 6 252 255 2 254 EIA 4 1 242 241 2 252 255 1 255 EIA 5 7 244 234 2 251 253 1 254 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 4 248 246 7 253 0 1 255 2000 ft. 24 awg 3 247 247 8 253 0 1 255 2000 ft 26 awg 2 246 249 7 252 1 1 255 Rev. 0.6 AN84 Table 19. ACIM = 0000 and CO Termination = 220 + 820 + 150 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 6 246 239 5 253 255 2 255 EIA 1 3 246 241 2 254 255 1 255 EIA 2 3 245 240 1 252 254 1 255 EIA 3 5 242 238 4 250 255 0 254 EIA 4 1 242 241 2 251 254 0 254 EIA 5 7 244 234 2 250 252 0 253 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 6 249 237 2 255 253 2 254 2000 ft. 24 awg 5 247 239 3 254 254 2 255 2000 ft 26 awg 3 246 241 2 254 255 1 255 Table 20. ACIM = 0000 and CO Termination = 600 + 1.5 µF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 255 254 254 254 254 254 254 254 EIA 1 255 246 253 3 251 0 254 254 EIA 2 2 242 241 7 252 254 1 253 EIA 3 5 240 237 8 252 254 1 253 EIA 4 1 242 241 2 252 255 0 254 EIA 5 7 244 234 1 251 253 1 254 EIA 6 4 244 228 6 7 247 1 253 EIA 7 248 230 8 18 234 2 1 255 2000 ft. 22 awg 1 249 251 2 251 255 254 254 2000 ft. 24 awg 0 247 252 3 251 0 254 254 2000 ft 26 awg 255 246 253 3 251 0 254 254 Rev. 0.6 19 AN84 Table 21. ACIM = 0010 and CO Termination = 220 + 120 + 115 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 9 16 5 254 2 255 0 0 EIA 1 2 10 9 255 1 0 255 1 EIA 2 255 0 3 2 0 1 0 0 EIA 3 1 253 0 4 254 1 0 0 EIA 4 253 252 0 255 0 0 0 0 EIA 5 4 253 249 255 254 255 0 255 EIA 6 1 254 242 4 8 246 2 254 EIA 7 244 241 19 11 244 2 253 1 2000 ft. 22 awg 6 15 6 254 3 255 0 0 2000 ft. 24 awg 5 12 7 255 2 0 0 0 2000 ft 26 awg 2 10 9 255 1 0 255 1 Table 22. ACIM = 0011 and CO Termination = 220 + 820 + 115 nF Line Type 20 Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 0 0 0 0 0 0 0 EIA 1 255 0 255 254 1 255 0 0 EIA 2 255 0 253 252 255 254 255 0 EIA 3 1 254 252 253 253 255 255 255 EIA 4 253 255 255 251 254 254 254 255 EIA 5 4 0 249 252 253 253 254 254 EIA 6 1 1 242 2 9 245 3 253 EIA 7 245 243 18 10 245 0 253 1 2000 ft. 22 awg 1 2 252 255 1 254 1 255 2000 ft. 24 awg 0 1 253 255 1 255 0 0 2000 ft 26 awg 255 0 255 254 1 255 0 0 Rev. 0.6 AN84 Table 23. ACIM = 0100 and CO Termination = 370 + 620 + 310 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 0 0 0 0 0 0 0 EIA 1 254 252 2 1 255 1 255 0 EIA 2 255 248 253 4 253 0 0 255 EIA 3 1 246 251 6 252 1 0 255 EIA 4 252 247 253 2 253 0 255 255 EIA 5 3 248 246 3 252 255 255 254 EIA 6 0 249 240 8 8 247 2 254 EIA 7 244 236 18 14 241 5 254 1 2000 ft. 22 awg 1 255 255 0 255 0 0 0 2000 ft. 24 awg 0 253 0 1 255 1 0 0 2000 ft 26 awg 254 252 2 1 255 1 255 0 Table 24. ACIM = 0100 and CO Termination = 220 + 820 + 120 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 248 254 6 255 2 1 0 EIA 1 254 249 253 4 255 1 1 0 EIA 2 255 249 251 2 254 0 0 0 EIA 3 1 246 250 4 252 1 0 255 EIA 4 252 247 253 1 253 0 255 255 EIA 5 3 248 246 2 252 254 255 254 EIA 6 0 249 240 8 8 247 2 254 EIA 7 244 236 18 14 241 5 254 1 2000 ft. 22 awg 1 251 249 5 0 0 2 255 2000 ft. 24 awg 0 249 251 5 255 0 1 0 2000 ft 26 awg 254 249 253 4 255 1 1 0 Rev. 0.6 21 AN84 Table 25. ACIM = 0101 and CO Termination = 300 + 1000 + 220 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 1 0 255 1 0 0 0 0 EIA 1 254 255 2 0 255 1 0 0 EIA 2 255 252 0 2 254 0 255 255 EIA 3 1 249 255 4 252 1 255 255 EIA 4 252 250 1 1 254 0 255 255 EIA 5 3 251 251 2 253 255 255 254 EIA 6 0 252 244 8 9 247 3 254 EIA 7 244 239 21 14 244 5 254 1 2000 ft. 22 awg 1 1 254 255 1 255 0 0 2000 ft. 24 awg 0 0 0 0 0 0 0 0 2000 ft 26 awg 254 255 2 0 255 1 0 0 Table 26. ACIM = 0101 and CO Termination = 370 + 620 + 310 nF Line Type 22 Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 4 4 0 1 1 0 1 EIA 1 254 0 6 1 0 2 255 1 EIA 2 255 252 1 3 254 1 0 0 EIA 3 1 249 255 5 253 1 0 255 EIA 4 252 250 1 2 255 0 255 0 EIA 5 3 251 250 3 254 255 255 255 EIA 6 0 252 244 8 9 247 3 254 EIA 7 244 239 21 14 244 5 254 1 2000 ft. 22 awg 1 3 3 0 1 0 0 0 2000 ft. 24 awg 0 1 4 1 0 1 0 0 2000 ft 26 awg 254 0 6 1 0 2 255 1 Rev. 0.6 AN84 Table 27. ACIM = 0101 and CO Termination = 270 + 750 + 150 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 0 254 2 4 1 2 1 0 EIA 1 254 253 2 3 1 2 1 1 EIA 2 255 252 0 2 255 1 0 0 EIA 3 1 249 254 4 253 1 0 0 EIA 4 252 250 1 1 254 0 255 0 EIA 5 3 251 250 2 253 255 255 255 EIA 6 0 252 244 8 9 247 3 254 EIA 7 244 239 21 14 244 5 254 1 2000 ft. 22 awg 1 0 255 3 2 0 1 0 2000 ft. 24 awg 0 254 0 3 1 1 1 0 2000 ft 26 awg 254 253 2 3 1 2 1 1 Table 28. ACIM = 1010 and CO Termination = 200 + 560 + 100 nF Line Type Hybrid Coefficient # 1 2 3 4 5 6 7 8 EIA 0 1 2 1 0 0 0 0 0 EIA 1 255 1 0 255 1 255 0 0 EIA 2 255 255 252 252 0 255 0 0 EIA 3 1 253 250 254 254 255 0 0 EIA 4 253 253 253 251 255 254 255 0 EIA 5 3 254 246 252 253 253 255 254 EIA 6 1 255 239 1 8 245 3 253 EIA 7 244 242 16 9 245 0 254 1 2000 ft. 22 awg 2 4 253 255 2 254 1 0 2000 ft. 24 awg 1 2 254 255 1 255 1 0 2000 ft 26 awg 255 1 0 255 1 255 0 0 Rev. 0.6 23 AN84 APPENDIX C—EIA LINE MODELS EIA1 EO EIA2 EO 2 kft 26 AWG 4 kft 26 AWG 3 kft 24 AWG EIA3 EO 7 kft 26 AWG EIA4 EO 12 kft 26 AWG EIA5 EO EIA6 EO EIA7 EO NI 1.5 kft 26 AWG 3 kft 24 AWG 88 88 6 kft 24 AWG 6 kft 24 AWG 88 88 6 kft 24 AWG 88 88 6 kft 22 AWG 6 kft 22 AWG Figure 9. EIA Line Models 24 1.5 kft 26 AWG 6 kft 24 AWG 6 kft 24 AWG Rev. 0.6 NI NI 9 kft 24 AWG 3 kft 24 AWG NI 88 88 9 kft 22 AWG 6 kft 22 AWG 88 NI NI 3 kft 22 AWG NI 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 Smart. Connected. Energy-Friendly Products Quality Support and Community www.silabs.com/products www.silabs.com/quality community.silabs.com Disclaimer Silicon Laboratories intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using or intending to use the Silicon Laboratories products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific device, and "Typical" parameters provided can and do vary in different applications. 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