PCM Encoding
Digital transmission systems are steadily replacing analog systems in commercial communications applications. This is especially true in telecommunications. that being the cases, an understanding of digital transmissions systems in the telecommunications industry. read more...
To perform the Experiment please follow the procedure:
1. Install run time engine program to operate each VI.
2. Activate
the DMM and
scope by press the
from
the tool bar, and then press the
in
each.
3. Set the VarDC’s output to 0 V.
4. Unplug the patch lead connected to the ground socket.
5. Determine the 7-bit number on the PCM Encoder module’s output.
6. Increase the VarDC VI’s output voltage in small increments in the negative direction and note what happens to binary number on the PCM Encoder module’s output.
7. What happens to the binary number as the input voltage increases in the negative direction?
8. Determine the first instance of the changing negative voltage that produce the number 0000000 on the PCM Encoder module’s output.
9. Record this voltage in table 1.
| PCM Encoder's output number | PCM Encoder's input voltage |
| 0000000 |
10. Return the VarDC VI’s output to 0 V.
11. Increase the VarDC VI’s output voltage in small increments in the positive direction and note what happens to binary number on the PCM Encoder module’s output.
12. What happens to the binary number as the input voltage increases in the positive direction?
13. Determine the first instance of the changing positive voltage that produce the number 1111111 on the PCM Encoder module’s output.
14. Record this voltage in table 2.
| PCM Encoder's output number | PCM Encoder's input voltage |
| 0000000 |
15. Based on the information in table 1 and 2, what is the maximum allowable peak-to-peak voltage for an AC signal on the PCM Encoder module’s input?
16. Calculate the difference between the PCM Encoder module’s quantization levels by subtracting the values in table 1 and 2 and dividing the number by 128.