Le79228
Data Sheet
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
Table 2. Minimum Specifications for Out-of-Band Input Signals
Frequency of Out-of-Band Signal
16.6 Hz < f < 45 Hz
Amplitude of Out-of-Band Signal
–25 dBm0 < A ≤ 0 dBm0
Level below A
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
4600 Hz < f < 100 kHz
–25 dBm0 < A ≤ 0 dBm0
–25 dBm0 < A ≤ 0 dBm0
see Figure 10
32 dB
Figure 10. Discrimination Against Out-of-Band Signals
0
-10
-20
-28 dBm
-30
-40
-50
Level (dB)
-32 dB, -25 dBm0 < input , 0 dBm0
3.4
4.0
4.6
Frequency (kHz)
Note:
The attenuation of the waveform below amplitude A between 3400 Hz and 4600 Hz is given by the formula:
π(4000 – f)
----------------------------
Attenuation (db) = 14 – 14sin
1200
Spurious Out-of-Band Signals at the Analog Output
With PCM code words representing a sine wave signal in the range of 300 Hz to 3400 Hz at a level of 0 dBm0 applied to the
digital input, the level of the spurious out-of-band signals at the analog output is less than the limits shown below.
Table 3. Limits for Spurious Out-of-Band Signals
Frequency
Level
4.6 kHz to 40 kHz
40 kHz to 240 kHz
240 kHz to 1 MHz
–32 dBm0
–46 dBm0
–36 dBm0
19
Zarlink Semiconductor Inc.
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