24

Am79D2251

Discrimination against Out-of-Band Input Signals

When an out-of-band sine wave signal with frequency and level A is applied to the analog input, there may be

frequency components below 4 kHz at the digital output which are caused by the out-of-band signal. These

components are at least the specified dB level below the level of a signal at the same output originating from a

1014 Hz sine wave signal with a level of A dBm0 also applied to the analog input. The minimum specifications are

shown in the following table.

Frequency of Out-of-Band Signal

Amplitude of Out-of-Band Signal

Level below A

16.6 Hz < f < 45 Hz

–25 dBm0 < A

≤ 0 dBm0

18 dB

45 Hz < f < 65 Hz

–25 dBm0 < A

≤ 0 dBm0

25 dB

65 Hz < f < 100 Hz

–25 dBm0 < A

≤ 0 dBm0

10 dB

3400 Hz < f < 4600 Hz

–25 dBm0 < A

≤ 0 dBm0

see Figure 12

4600 Hz < f < 100 kHz

–25 dBm0 < A

≤ 0 dBm0

32 dB

0

–10

–20

–30

–40

–50

Frequency (kHz)

3.4

4.0

4.6

–32 dB, –25 dBm0 < input < 0 dBm0

ISLAC Device Specification

Level (dB)

19256A-012

–28 dBm

Note:

The attenuation of the waveform below amplitude A between

3400 Hz and 4600 Hz is given by the formula:

Attenuation (db)

14

14

–

()

1200

--------------------------

sin

–

=

Figure 12. Discrimination Against Out-of-Band Signals