PCM-TDM 'T1' implementation
A technique in telecommunications known as Time Division Multiple Access (TDMA). The principles underpinning bit-clock regenerations and demonstrated how it can be used to generate a local bit-clock for a PCM decoder from a PCM data signal. For more information back to PCM and TDMA.
To perform the Experiment please follow the procedure:
1. Install the run time engine program to operate each VI.
2. Activate
the
functions generator and
scope
by pressing
the
from
the tool bar, and then press the
in
each.
3. Adjust the function generator using its soft controls for an output with the following specifications:
|
Wave Form Shape |
Sinusoidal |
|
Frequency |
1 Hz |
|
Amplitude |
5 Vp-p |
|
DC offset |
0 V |
4. Select one of the transmitter modules and set its mode control to DIGITAL.
5. Select one the Receiver modules and set its Gain range control to LO.
6. Turn the same Receiver module's Variable Gain control fully counter-clockwise
7. Verify that the system is still encoding. Decoding and reconstructing message-2
8. To prove that the optical patch lead is now the system's channel carrying the PCM-TDM data, momentarily disconnect it at either end.
9. Launch and run the NI ELVIS II Oscilloscope VI. and Set the values for the scope as follows:
|
Channel 0 |
Channel 1 |
|
|
Volts/Div |
1 V |
1 V |
|
DC offset |
0 V |
0 V |
|
Time/Div |
500 µ sec | 500 µ sec |
10. Take a screen shoot for Ch 1 " Received Signal ".
11. Verify that the system is still encoding, decoding and reconstructing message-1(ignoring distortion)
12. Momentarily disconnect either end of the optical patch lead to check that you lose the reconstructed message.