PEB2465 SIEMENS [Siemens Semiconductor Group], PEB2465 Datasheet - Page 82

• Manufacturer Part Number: PEB2465
• Description: Four Channel Codec Filter
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Semiconductor Group
10.3.4 Using the Level Metering Function
Task
An external sine wave (applied to the analog input pin
sine wave signal (via tone generator TG1 or via test loops) is send to the SICOFI-4
transmit path. This signal will be rectified and the power of this signal will be compared
to the programmable offset value of the level metering function. If the measured power
exceeds a certain value the LMR bit of the register CR2 is set to ‘1’.
In the appendix you will find a printout of the Track file to test the SICOFI-4 level metering
function.
The following steps show how to detect a sine wave with a frequency of 2 kHz and a
PCM level L = 0 dB (like measured with the PCM4 in the A/D measurement).
Step 1
The SICOFI-4 extended register XR4 holds the offset value for the level metering
function. With the QSICOS utility program ‘Calculation of Level Metering Function’ the
programming byte for this register XR4 can be calculated. In our case the Level L will be
0 dB.
Bytes for Level Metering Register XR4: 71
Step 2
The level metering function is always used together with a bandpass filter. The
programming of this bandpass filter has to be done by programming the tone-generator
coefficients of the tone generator TG2. (During Level Metering Function enabled, TG2 is
not available). For this example the coefficients of the TG2 for a frequency of
have to be calculated using the QSICOS utility program ‘Calculate Tone Generator
Coefficients’:
Bytes for Tone Generator 2 (0D): 00, 80, 40, 09
Step 3
The SICOFI-4 extended register XR4 has to be programmed.
Step 4
In the SICOFI-4 configuration register CR2 the level metering bit LM has to be set to ‘1’
and the programmed frequency for the tone generator 2 has to chosen by setting the
PTG2 bit to ‘1’.
Example for writing the CR2 register: 0 0 1 0 0 0 1 0 = 22
82
V
IN
H
) or an internally generated
(A-Law is selected)
f
PEB 2465
Appendix
= 2000 Hz
02.97