AM79Q4457J ETC1 [List of Unclassifed Manufacturers], AM79Q4457J Datasheet - Page 19

• Manufacturer Part Number: AM79Q4457J
• Description: Quad Subscriber Line Audio Processing Circuit-Non-Programmable (QSLAC-NP) Devices
• Manufacturer: ETC1 [List of Unclassifed Manufacturers]

Discrimination against 12 kHz and
16 kHz Metering Signals
If the QSLAC-NP device is used in a metering applica-
tion where 12 kHz or 16 kHz tone bursts are injected
onto the telephone line toward the subscriber, a portion
of those tones may also appear at the I
These out-of-band signals may cause frequency com-
ponents to appear below 4 kHz at the digital output.
For a 12 kHz or 16 kHz tone, the frequency compo-
nents below 4 kHz will be reduced from the input by at
least 70 dB. The sum of the peak metering and signal
currents must be within the analog input current range.
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
Level (dBm0)
–10
–20
–30
–40
–50
0
Figure 6. Spurious Out-of-Band Signals
3.4
IN
terminal.
SLAC Products
4.0
Frequency (kHz)
out-of-band signals at the analog output is less than
the limits shown in the following table.
With code words representing any sine wave signal in
the range 3.4 kHz to 4.0 kHz at a level of 0 dBm0 ap-
plied to the digital input, the level of the signals at the
analog output are below the limits in Figure 6. The am-
plitude of the spurious out-of-band signals between
3400 Hz and 4600 Hz is given by the formula:
4.6
QSLAC-NP Device Specification
40 kHz to 240 kHz
240 kHz to 1 MHz
4.6 kHz to 40 kHz
–28 dB
Frequency
A
=
–
14
–
14
sin
–32 dB
--------------------------- - dBm0
f 4000
1200
–
–32 dBm0
–46 dBm0
–36 dBm0
Level
19256A-013
19