LE58QL021BVC Zarlink, LE58QL021BVC Datasheet - Page 19

• Manufacturer Part Number: LE58QL021BVC
• Description: QUAD, SLAC, PROG CODEC, 3.3V, 20 I/0, PQT44, LEAD FREE
• Manufacturer: Zarlink

Discrimination Against Out-of-Band Input Signals
When an out-of-band sine wave signal of frequency f, 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.
Note:
The attenuation of the waveform below amplitude A, between 3400 Hz and 4600 Hz, is given by the formula:
Discrimination Against 12- and 16-kHz Metering Signals
If the QLSLAC device is used in a metering application where 12 kHz or 16 kHz tone bursts are injected onto the telephone line
toward the subscriber, a portion of these tones also may appear at the VIN terminal. These out-of-band signals may cause
frequency components to appear below 4 kHz at the digital output. For a 12 kHz or 16 kHz tone, the frequency components below
4 kHz are reduced from the input by at least 70 dB. The sum of the peak metering and signal voltages must be within the analog
input voltage range.
Frequency of Out-of-Band Signal
3400 Hz < f < 4600 Hz
4600 Hz < f < 100 kHz
16.6 Hz < f < 45 Hz
65 Hz < f < 100 Hz
45 Hz < f < 65 Hz
Level below
A (dB)
Figure 11. Discrimination Against Out-of-Band Signals
-10
-20
-30
-40
-50
0
Attenuation (db)
3.4
Zarlink Semiconductor Inc.
Amplitude of Out-of-Band Signal
=
–25 dBm0 < A ≤ 0 dBm0
–25 dBm0 < A ≤ 0 dBm0
–25 dBm0 < A ≤ 0 dBm0
–25 dBm0 < A ≤ 0 dBm0
–25 dBm0 < A ≤ 0 dBm0
4.0
Frequency (kHz)
14 14
19
–
sin


4.6
π 4000 f –
---------------------------- -
(
1200
)


-28 dB
-32 dB
Level below A
see Figure 11
18 dB
25 dB
10 dB
32 dB