AD4134 datasheet(42/92 Pages) AD

42 / 92 page

Data Sheet

AD4134

CIRCUIT INFORMATION

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Rev. 0 | 42 of 92

Figure 79. Sinc3 Filter Step Response

Simultaneous 50 Hz and 60 Hz Rejection

Because the sinc filter rejects signals at the frequency around

integer multiples of the ODR, it can be used to reject undesired

interference at a specific frequency higher than the input band

of interest. Because the sinc3 filter supports an ODR down to

10 SPS, a typical application for the sinc3 filter is to make dc to low

bandwidth measurements while rejecting line frequencies at 50 Hz

or 60 Hz.

Figure 80 shows the frequency response of the sinc3 filter when the

output data rate is programmed to 50 SPS. The sinc3 filter provides

102 dB rejection at 50 Hz ± 1 Hz.

Figure 80. Sinc3 and Sinc6 Filter Response (ODR = 50 SPS)

Figure 81 shows the frequency response of the sinc3 filter when the

output data rate is programmed to 60 SPS. The sinc3 filter provides

106 dB rejection at 60 Hz ± 1 Hz.

Figure 81. Sinc3 and Sinc6 Filter Response (ODR = 60 SPS)

When the output data rate is 10 SPS, simultaneous 50 Hz and

60 Hz rejection is obtained. The sinc3 filter provides 102 dB rejec-

tion at 50 Hz ± 1 Hz and 105 dB at 60 Hz ± 1 Hz.

Figure 82. Sinc3 and Sinc6 Filter Response (ODR = 10 SPS)

Simultaneous 50 Hz and 60 Hz rejection can also be achieved by

selecting the sinc3 and 50 Hz/60 Hz rejection filter path. When

the sinc3 filter places a notch at 50 Hz, the 50 Hz/60 Hz rejection

postfilter places a first-order notch at 60 Hz. The output data rate is

50 SPS. Figure 83 shows the frequency response of the sinc3 and

50 Hz/60 Hz rejection filter path. The rejection at 50 Hz and 60 Hz

(±1 Hz) is in excess of 67 dB.

AD4134 Datasheet(PDF) 42 Page - Analog Devices