AN-1374 APPLICATION NOTE One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com ADE7912/ADE7913 Front-End DSP Specifications by Gabriel Antonesei INTRODUCTION DIGITAL DECIMATION FILTERING Functional Description Figure 1 shows the block diagram of the decimation filtering implemented in the ADE7912/ADE7913. The Σ-Δ modulator provides a bit stream with a frequency of 1 MHz when the chip is clocked at CLKIN = 4.096 MHz. The SINC4 filter uses four decimation ratios—32, 64, 128, and 256—to provide outputs at 32 kHz, 16 kHz, 8 kHz and 4 kHz. To limit the bandwidth to meaningful frequencies while also keeping the data rate as low as possible, an extra low-pass filter (LPF) with 60 dB attenuation is used. This makes the subsequent rms and power calculations ANALOG INPUT Σ-∆ 1MHz SINC4 ↓ (32, 64, 128, OR 256) more precise, reducing the bandwidth a micro-controller must reserve for the metrology calculations. The LPF performs another decimation by 4, and has internal flexibility, which leads to two different bandwidths. The LPF is implemented as two separate, sixth-order filters: one filter for the narrower bandwidths, one filter for the larger bandwidths. The ADE7912/ADE7913 provide multiple output data rates (ODRs): 8 kHz, 4 kHz, 2 kHz, and 1 kHz, as well as two selectable bandwidths for each of these rates (see Table 1). The selectable ODRs help users address a wide range of scenarios to make their own trade-offs in the datapaths implemented in the microcontroller. ODR and bandwidth selection is performed by Bit 7 (BW) and Bits[5:4] (ADC_FREQ) in the CONFIG register. Table 1 shows the different BW and ADC_FREQ settings required when the ADE7912/ADE7913 is clocked at CLKIN = 4.096 MHz. The bandwidth is indicated by the point at which the gain is attenuated by 3 dB. 32kHz ... 4kHz DIGITAL OUTPUT LPF ↓4 (6TH ORD.) 8kHz ... 1kHz 13429-001 This application note explains several aspects of the digital filtering associated with the Σ-Δ modulators used in the ADE7912/ ADE7913. The role of the filters is to decimate the outputs of the modulators to various rates, while eliminating high frequency noise. These rates start from a high of 8 kHz and go as low as 1 kHz, allowing the user to update the rates to the microcontroller processing bandwidth. Figure 1. Block Diagram of the Decimation Filtering Implemented in the ADE7912/ADE7913 Table 1. CONFIG Register Settings for Obtaining Various ODRs and Bandwidths CONFIG Register Bits[5:4] (ADC_FREQ) Setting Bit 7 (BW) Setting 00 0 00 1 01 0 01 1 10 0 10 1 11 0 11 1 ODR (kHz) 8 8 4 4 2 2 1 1 Rev. 0 | Page 1 of 15 SINC4 + LPF Bandwidth (kHz) 3.338 2.137 1.670 1.069 0.836 0.535 0.418 0.268 AN-1374 Application Note TABLE OF CONTENTS Introduction ...................................................................................... 1 Digital Decimation Filtering ....................................................... 1 Revision History ............................................................................... 2 Frequency Response and Time Delay Characteristics of the SINC + LPF Filters ........................................................................3 Magnitude Frequency Response and Time Delays for Various Filters...............................................................................................4 REVISION HISTORY 8/15—Revision 0: Initial Version Rev. 0 | Page 2 of 15 Application Note AN-1374 FREQUENCY RESPONSE AND TIME DELAY CHARACTERISTICS OF THE SINC4 + LPF FILTERS The equivalent Z-domain formula of the SINC4 for various decimation ratios (DRs) is shown in the following equation: 1 z DR SINC4 (z) = 1 1 z 4 The Z-domain formula of the LPF that corresponds to the narrower bandwidth (BW, Bit 7 of the CONFIG register, is set to 1) is shown in the following equation: LPF_BW1 (z) = (1 1.15478515625 z 1 ) (1 0.7138671875 z 1 ) (1 0.6630859375 z 1 z 2 ) (1 1.333984375 z 1 z 2 ) (1 1.5068359375 z 1 0.6162109375 z 2 ) (1 0.6962890625 z 1 0.8544921875 z 2 ) where LPF_BW1 is the LPF that corresponds to the narrower bandwidth. The Z-domain formula of the LPF that corresponds to the larger bandwidth (BW, Bit 7 of the CONFIG register, is cleared to 0) is shown in the following equation: LPF_BW2 (z)= (1 1.15478515625 z 1 z 2 ) (1 1.205322265625 z 1 0.385498046875 z 2 ) (1 0.603759765625 z 1 z 2 ) (1 1.31005859375 z 1 0.589111328125 z 2 ) (1 1.0595703125 z 1 z 2 ) (1 1.470947265625 z 1 0.856201171875 z 2 ) where LPF_BW2 is the LPF that corresponds to the larger bandwidth. Rev. 0 | Page 3 of 15 AN-1374 Application Note MAGNITUDE FREQUENCY RESPONSE AND TIME DELAYS FOR VARIOUS FILTERS Figure 2 through Figure 25 and Table 2 through Table 32 provide detailed information about the magnitude frequency response and the time delays introduced in the signal path by the various filters. The output data rate (ODR) is the output frequency at which the analog-to-digital converter (ADC) samples are provided by the ADE7912/ADE7913. The bandwidth of the filter (BW) is the point at which the gain is attenuated by 3 dB. The full frequency response, or the response up to the −3 dB point, and the flat-band response (from 0 dB down to −0.8 dB attenuation) are shown in all ODR and BW cases. The phase delay defines the propagation delay in the phase of a sinusoidal signal passing through the filter. Tables showing the phase delay at various frequencies are shown for all ODR and BW cases. From the perspective of power calculations, these time delays do not affect the final results because both voltage and current signals are subject to identical time delay propagation. However, in case of transient events or events synchronous to the zero crossings, it may be useful to know the time delays. The frequency points are selected in such a way that the intermediate values can be obtained with accuracy by piecewise linear interpolation. These frequency points may be useful, for example, if amplitude corrections are necessary. Rev. 0 | Page 4 of 15 Application Note AN-1374 ODR = 8 kHz and BW = 3.338 kHz –10 –20 –30 –40 –50 –60 –70 –80 0 2000 4000 6000 8000 10000 12000 14000 16000 FREQUENCY (Hz) 0 –0.1 –0.2 –0.3 –0.4 –0.5 –0.6 –0.7 –0.8 0 500 1000 1500 2000 2500 3000 3500 FREQUENCY (Hz) Figure 2. Full Frequency Response for ODR = 8 kHz and BW = 3.338 kHz 13429-004 MAGNITUDE FREQUENCY RESPONSE (dB) 0.1 13429-002 MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 4. Flat-Band Response for ODR = 8 kHz and BW = 3.338 kHz –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 0 500 1000 1500 2000 2500 3000 3500 FREQUENCY (Hz) 13429-003 MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 3. 3 dB Point Response for ODR = 8 kHz and BW = 3.338 kHz Table 2. SINC4 + LPF Gain Response at Various Frequencies for ODR = 8 kHz and BW = 3.338 kHz; Frequency Range = 50 Hz to 450 Hz 50 0 Magnitude (milli_dB) 100 −0.32 150 −0.87 Frequency (Hz) 250 300 −2.67 −3.93 200 −1.66 350 −5.44 400 −7.21 450 −9.26 Table 3. SINC4 + LPF Gain Response at Various Frequencies for ODR = 8 kHz and BW = 3.338 kHz; Frequency Range = 500 Hz to 900 Hz Magnitude (milli_dB) 500 −11.6 550 −14.22 600 −17.15 650 −20.40 Frequency (Hz) 700 750 −23.97 −27.87 800 −32.11 850 −36.69 900 −41.61 Table 4. SINC4 + LPF Gain Response at Various Frequencies for ODR = 8 kHz and BW = 3.338 kHz; Frequency Range = 950 Hz to 1350 Hz Magnitude (milli_dB) 950 −46.86 1000 −52.45 1050 −58.37 1100 −64.6 Frequency (Hz) 1150 1200 −71.13 −77.95 1250 −85.05 1300 −92.41 1350 −100 Table 5. SINC4 + LPF Gain Response at Various Frequencies for ODR = 8 kHz and BW = 3.338 kHz; Frequency Range = 1400 Hz to 2200 Hz Magnitude (dB) 1400 −0.108 1500 −0.124 1600 −0.141 1700 −0.159 Frequency (Hz) 1800 1900 −0.177 −0.197 Rev. 0 | Page 5 of 15 2000 −0.218 2100 −0.241 2200 −0.265 AN-1374 Application Note Table 6. SINC4 + LPF Gain Response at Various Frequencies for ODR = 8 kHz and BW = 3.338 kHz; Frequency Range = 2300 Hz to 3100 Hz Magnitude (dB) 2300 −0.291 2400 −0.318 2500 −0.346 2600 −0.374 Frequency (Hz) 2700 2800 −0.402 −0.434 2900 −0.486 3000 −0.6 3100 −0.859 Table 7. SINC4 + LPF Gain Response at Various Frequencies for ODR =8 kHz and BW = 3.338 kHz; Frequency Range = 3200 Hz to 3500 Hz 3200 −1.414 Magnitude (dB) 3300 −2.452 Frequency (Hz) 3338 −3.0 3400 −4.09 3500 −6.27 Table 8. SINC4 +LPF Phase Delay Response at Various Frequencies for ODR = 8 kHz and BW = 3.338 kHz Phase Delay (μs) 50 225 500 226 750 227 1000 229 Frequency (Hz) 1500 2000 234 241 Rev. 0 | Page 6 of 15 2500 254 3000 277 3300 321 Application Note AN-1374 ODR = 8 kHz and BW = 2.137 kHz 0.1 –20 –30 –40 –50 –60 –70 –80 0 2000 4000 6000 8000 10000 12000 14000 16000 FREQUENCY (Hz) 0 –0.1 –0.2 –0.3 –0.4 –0.5 –0.6 –0.7 –0.8 0 500 1000 1500 2000 2500 FREQUENCY (Hz) Figure 5. Full Frequency Response for ODR = 8 kHz and BW = 2.137 kHz 13429-007 MAGNITUDE FREQUENCY RESPONSE (dB) –10 13429-005 MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 7. Flat-Band Response for ODR = 8 kHz and BW = 2.137 kHz –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 0 500 1000 1500 2000 2500 FREQUENCY (Hz) 13429-006 MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 6. 3 dB Point Response for ODR = 8 kHz and BW = 2.137 kHz Table 9. SINC4 + LPF Gain Response at Various Frequencies for ODR = 8 kHz and BW = 2.137 kHz; Frequency Range = 50 Hz to 450 Hz Magnitude (milli_dB) 50 0 100 −0.56 150 −1.5 Frequency (Hz) 250 300 −4.34 −6.19 200 −2.77 350 −8.25 400 −10.51 450 −12.91 Table 10. SINC4 + LPF Gain Response at Various Frequencies for ODR = 8 kHz and BW = 2.137 kHz; Frequency Range = 500 Hz to 900 Hz 500 −15.44 Magnitude (milli_dB) 550 −18.08 600 −20.82 650 −23.68 Frequency (Hz) 700 750 −26.70 −29.90 800 −33.36 850 −37.13 900 −41.29 Table 11. SINC4 + LPF Gain Response at Various Frequencies for ODR = 8 kHz and BW = 2.137 kHz; Frequency Range = 950 Hz to 1400 Hz Magnitude (milli_dB) 950 −45.90 1000 −51.01 1050 −56.64 1100 −62.8 Frequency (Hz) 1150 1200 −69.41 −76.40 Rev. 0 | Page 7 of 15 1250 −83.64 1300 −90.96 1400 −105 AN-1374 Application Note Table 12. SINC4 + LPF Gain Response at Various Frequencies for ODR = 8 kHz and BW = 2.137 kHz; Frequency Range = 1500 Hz to 2200 Hz Magnitude (dB) 1500 −0.119 1600 −0.140 1700 −0.188 1800 −0.314 Frequency (Hz) 1900 2000 −0.621 −1.274 2100 −2.243 2137 −3.01 2200 −4.167 Table 13. SINC4 + LPF Phase Delay Response at Various Frequencies for ODR = 8 kHz and BW = 2.137 kHz Phase Delay (μs) 50 294 500 296 750 299 1000 304 Rev. 0 | Page 8 of 15 Frequency (Hz) 1500 322 1750 338 2000 365 2100 377 Application Note AN-1374 ODR = 4 kHz and BW = 1.67 kHz 0.1 –20 –30 –40 –50 –60 –70 –80 0 1000 2000 3000 4000 5000 6000 7000 8000 FREQUENCY (Hz) 0 –0.1 –0.2 –0.3 –0.4 –0.5 –0.6 –0.7 –0.8 0 200 400 600 800 1000 1200 1400 1600 1800 FREQUENCY (Hz) Figure 8. Full Frequency Response for ODR = 4 kHz and BW = 1.67 kHz 13429-010 MAGNITUDE FREQUENCY RESPONSE (dB) –10 13429-008 MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 10. Flat-Band Response for ODR = 4 kHz and BW = 1.67 kHz –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 0 200 400 600 800 1000 1200 1400 1600 1800 FREQUENCY (Hz) 13429-009 MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 9. 3 dB Point Response for ODR = 4 kHz and BW = 1.67 kHz Table 14. SINC4 + LPF Gain Response at Various Frequencies for ODR = 4 kHz and BW = 1.67 kHz; Frequency Range = 50 Hz to 450 Hz Magnitude (milli_dB) 50 0 100 −1.323 150 −3.589 200 −6.865 Frequency (Hz) 250 300 −11.234 −16.784 350 −23.596 400 −31.732 450 −41.222 Table 15. SINC4 + LPF Gain Response at Various Frequencies for ODR = 4 kHz and BW = 1.67 kHz; Frequency Range = 500 Hz to 900 Hz Magnitude (milli_dB) 500 −52.06 550 −64.199 600 −77.554 650 −92.011 Frequency (Hz) 700 750 −107.44 −123.73 800 −140.81 850 −158.66 900 −177.37 Table 16. SINC4 + LPF Gain Response at Various Frequencies for ODR = 4 kHz and BW = 1.67 kHz; Frequency Range = 950 Hz to 1350 Hz Magnitude (dB) 950 −0.197 1000 −0.218 1050 −0.240 1100 −0.265 Frequency (Hz) 1150 1200 −0.291 −0.318 Rev. 0 | Page 9 of 15 1250 −0.346 1300 −0.373 1350 −0.401 AN-1374 Application Note Table 17. SINC4 + LPF Gain Response at Various Frequencies for ODR = 4 kHz and BW = 1.67 kHz; Frequency Range = 1400 Hz to 1900 Hz Magnitude (dB) 1400 −0.433 1450 −0.486 1500 −0.598 1550 −0.856 Frequency (Hz) 1600 1670 −1.407 −3.01 1700 −4.071 1800 −8.807 1900 −14.39 Table 18. SINC4 + LPF Phase Delay Response at Various Frequencies for ODR = 4 kHz and BW = 1.67 kHz Phase Delay (μs) 50 450 250 452 500 458 750 467 Frequency (Hz) 1000 483 Rev. 0 | Page 10 of 15 1250 508 1500 555 1650 608 Application Note AN-1374 ODR = 4 kHz and BW = 1.069 kHz 0.1 MAGNITUDE FREQUENCY RESPONSE (dB) –20 –30 –40 –50 –60 –70 –80 0 1000 2000 3000 4000 5000 6000 7000 0 –0.1 –0.2 –0.3 –0.4 –0.5 –0.6 –0.7 8000 –0.8 FREQUENCY (Hz) 0 200 400 600 800 1000 1200 FREQUENCY (Hz) Figure 11. Full Frequency Response for ODR = 4 kHz and BW = 1.069 kHz 13429-013 –10 13429-011 MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 13. Flat-Band Response for ODR = 4 kHz and BW = 1.069 kHz –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 0 200 400 600 800 1000 13429-012 MAGNITUDE FREQUENCY RESPONSE (dB) 0 1200 FREQUENCY (Hz) Figure 12. 3 dB Point Response for ODR = 4 kHz and BW = 1.069 kHz Table 19. SINC4 + LPF Gain Response at Various Frequencies for ODR = 4 kHz and BW = 1.069 kHz; Frequency Range = 50 Hz to 450 Hz Magnitude (milli_dB) 50 0 100 −2.19 150 −5.60 200 −9.92 Frequency (Hz) 250 300 −14.85 −20.23 350 −26.10 400 −32.76 450 −40.68 Table 20. SINC4 + LPF Gain Response at Various Frequencies for ODR = 4 kHz and BW = 1.069 kHz; Frequency Range = 500 Hz to 900 Hz Magnitude (milli_dB) 500 −50.39 550 −62.16 600 −75.77 650 −90.33 Frequency (Hz) 700 750 −104.7 −119.2 800 −139.8 850 −186.9 900 −311.5 Table 21. SINC4 + LPF Gain Response at Various Frequencies for ODR = 4 kHz and BW = 1.069 kHz; Frequency Range = 950 Hz to 1300 Hz Magnitude (dB) 950 −0.617 1000 −1.265 1050 −2.423 1069 −3.015 Frequency (Hz) 1100 1150 −4.147 −6.326 1200 −8.776 1250 −11.343 1300 −13.936 Table 22. SINC4 + LPF Phase Delay Response at Various Frequencies for ODR = 4 kHz and BW = 1.069 kHz Phase Delay (μs) 50 588 250 593 500 609 Rev. 0 | Page 11 of 15 Frequency (Hz) 750 643 1000 730 1250 795 AN-1374 Application Note ODR = 2 kHz and BW = 0.836 kHz 0.1 –20 –30 –40 –50 –60 –70 –80 0 500 1000 1500 2000 2500 3000 3500 4000 FREQUENCY (Hz) 0 –0.1 –0.2 –0.3 –0.4 –0.5 –0.6 –0.7 –0.8 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (Hz) Figure 14. Full Frequency Response for ODR = 2 kHz and BW = 0.836 kHz 13429-016 MAGNITUDE FREQUENCY RESPONSE (dB) –10 13429-014 MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 16. Flat-Band Response for ODR = 2 kHz and BW = 0.836 kHz –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (Hz) 13429-015 MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 15. 3 dB Point Response for ODR = 2 kHz and BW = 0.836 kHz Table 23. SINC4 + LPF Gain Response at Various Frequencies for ODR = 2 kHz and BW = 0.836 kHz; Frequency Range = 50 Hz to 450 Hz Magnitude (milli_dB) 50 0 100 −5.5 150 −15.37 200 −30.27 Frequency (Hz) 250 300 −50.55 −76 350 −106 400 −139 450 −176 Table 24. SINC4 + LPF Gain Response at Various Frequencies for ODR = 2 kHz and BW = 0.836 kHz; Frequency Range = 500 Hz to 1000 Hz Magnitude (dB) 500 −0.216 550 −0.263 600 −0.316 650 −0.372 700 −0.431 Frequency (Hz) 750 800 −0.594 −1.39 836 −3.05 850 −4.03 900 −8.75 950 −14.33 Table 25. SINC4 + LPF Phase Delay Response at Various Frequencies for ODR = 2 kHz and BW = 0.836 kHz Phase Delay (μs) 50 901 125 904 250 915 350 930 Frequency (Hz) 400 939 Rev. 0 | Page 12 of 15 500 965 750 1109 830 1223 1000 −20.0 Application Note AN-1374 ODR = 2 kHz and BW = 0.535 kHz 0.1 –10 –20 –30 –40 –50 –60 –70 0 500 1000 1500 2000 2500 3000 3500 4000 FREQUENCY (Hz) –0.1 –0.2 –0.3 –0.4 –0.5 –0.6 –0.7 –0.8 13429-017 –80 0 0 100 200 300 400 500 600 FREQUENCY (Hz) Figure 17. Full Frequency Response for ODR = 2 kHz and BW = 0.535 kHz 13429-019 MAGNITUDE FREQUENCY RESPONSE (dB) MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 19. Flat-Band Response for ODR = 2 kHz and BW = 0.535 kHz –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 0 100 200 300 400 500 600 FREQUENCY (Hz) 13429-018 MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 18. 3 dB Point Response for ODR = 2 kHz and BW = 0.535 kHz Table 26. SINC4 + LPF Gain Response at Various Frequencies for ODR = 2 kHz and BW = 0.535 kHz; Frequency Range = 50 Hz to 450 Hz 50 0 Magnitude (milli_dB) 100 −7.69 150 −17.99 200 −30.48 Frequency (Hz) 250 300 −48.05 −73.36 350 −102.34 400 −137.17 450 −305.62 Table 27. SINC4 + LPF Gain Response at Various Frequencies for ODR = 2 kHz and BW = 0.535 kHz; Frequency Range = 500 Hz to 750 Hz Magnitude (dB) 500 −1.24 535 −3.01 Frequency (Hz) 600 650 −8.72 −13.88 550 −4.10 700 −19.01 750 −24.03 Table 28. SINC4 + LPF Phase Delay Response at Various Frequencies for ODR = 2 kHz and BW = 0.535 kHz Phase Delay (μs) 50 1177 125 1185 250 1217 Frequency (Hz) 350 400 1268 1309 Rev. 0 | Page 13 of 15 500 1459 535 1525 AN-1374 Application Note ODR = 1 kHz and BW = 0.418 kHz 0.1 –10 –20 –30 –40 –50 –60 –80 0 200 400 600 800 1000 1200 1400 1600 1800 2000 FREQUENCY (Hz) –0.1 –0.2 –0.3 –0.4 –0.5 –0.6 –0.7 –0.8 13429-020 –70 0 0 50 100 150 200 250 300 350 400 450 500 FREQUENCY (Hz) Figure 20. Full Frequency Response for ODR = 1 kHz and BW = 0.418 kHz 13429-022 MAGNITUDE FREQUENCY RESPONSE (dB) MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 22. Flat-Band Response for ODR = 1 kHz and BW = 0.418 kHz –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 0 50 100 150 200 250 300 350 400 450 500 FREQUENCY (Hz) 13429-021 MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 21. 3 dB Point Response for ODR = 1 kHz and BW = 0.418 kHz Table 29. SINC4 + LPF Gain Response at Various Frequencies for ODR = 1 kHz and BW = 0.418 kHz; Frequency Range = 50 Hz to 600 Hz Magnitude (dB) 50 0 100 −0.024 150 −0.070 200 −0.133 250 −0.210 Frequency (Hz) 300 350 400 −0.310 −0.424 −1.355 418 −2.98 450 −8.64 500 −19.95 550 −31.74 600 −45.78 Table 30. SINC4 + LPF Phase Delay Response at Various Frequencies for ODR = 1 kHz and BW = 0.418 kHz Phase Delay (μs) 50 1806 100 1820 150 1843 Frequency (Hz) 200 250 1879 1930 Rev. 0 | Page 14 of 15 300 2005 350 2122 400 2349 Application Note AN-1374 ODR = 1 kHz and BW = 0.268 kHz 0.1 –10 –20 –30 –40 –50 –60 –80 0 200 400 600 800 1000 1200 1400 1600 1800 2000 FREQUENCY (Hz) –0.1 –0.2 –0.3 –0.4 –0.5 –0.6 –0.7 –0.8 13429-023 –70 0 0 50 100 150 200 250 300 FREQUENCY (Hz) Figure 23. Full Frequency Response for ODR = 1 kHz and BW = 0.268 kHz 13429-025 MAGNITUDE FREQUENCY RESPONSE (dB) MAGNITUDE FREQUENCY RESPONSE (dB) 0 Figure 25. Flat-Band Response for ODR = 1 kHz and BW = 0.268 kHz –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 0 50 100 150 200 250 13429-024 MAGNITUDE FREQUENCY RESPONSE (dB) 0 300 FREQUENCY (Hz) Figure 24. 3 dB Point Response for ODR = 1 kHz and BW = 0.268 kHz Table 31. SINC4 + LPF Gain Response at Various Frequencies for ODR = 1 kHz and BW = 0.268 kHz; Frequency Range = 50 Hz to 400 Hz Magnitude (dB) 50 0 100 −0.022 150 −0.065 200 −0.128 Frequency (Hz) 250 268 −1.20 −3.0 300 −8.615 350 −18.9 400 −28.91 Table 32. SINC4 + LPF Phase Delay Response at Various Frequencies for ODR = 1 kHz and BW = 0.268 kHz Phase Delay (μs) 50 2363 100 2402 ©2015 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. AN13429-0-8/15(0) Rev. 0 | Page 15 of 15 Frequency (Hz) 150 2477 200 2615 250 2913