SLAC Products
19
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
IN terminal.
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
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:
Frequency
Level
4.6 kHz to 40 kHz
–32 dBm0
40 kHz to 240 kHz
–46 dBm0
240 kHz to 1 MHz
–36 dBm0
A14
–
14
π f 4000
–
()
1200
---------------------------- dBm0
sin
–
=
0
–10
–20
–30
–40
–50
–28 dB
–32 dB
QSLAC-NP Device Specification
Frequency (kHz)
3.4
4.0
4.6
19256A-013
Level (dBm0)
Figure 6. Spurious Out-of-Band Signals
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
