AIMThe main purpose of this project is to demonstrate digitizing and companding pulse code on a signal and to observe the effects of sampling depth and companding on the ratio signal to noise (SQR).INTRODUCTIONPCM- In pulse code modulation (PCM), the signal is a digitally represented analog signal in which the amplitude of the signal is sampled at uniform intervals. Each sample is quantized to the closest value of the digital signal. In pulse code modulation, the signal is binary. The two possible states represented in PCM are logical 1 (high) and logical 0 (low). The main advantage of the PCM signal is that it derives from an analog signal that is multiplexed with data from the computer and carried on a common channel at high speed. COMPANDING - The combination of compression and expansion is known as companding. In compression, data is compressed before being sent and then expanded to the recipient using the same nonlinear scale. Noise and crosstalk levels at the receiver are reduced through compression. It is used in wireless microphones for better dynamic range and also in digital and telephony systems for compressing the input signal and expanding the output signal. Figure 1 below shows the demonstration of PCM with and without compansion. Figure 1- PCM with and without compandingProcedure to create PCM and companding on an Excel sheet PCM and companding of a signal is performed on a spreadsheet using Excel. First, you create a sine wave by varying time versus amplitude. The frequency of the signal is considered to be 10 Hz. The quantization process of the signal will be performed. A quantized sine wave is then created. Now the number of layers cells (N) should be created. Let's take the value...... in the center of the sheet......ude=0.1, large N=8.GRAPH I) Graph of SQR vs Amplitude with Companding (mu=255) and without Companding (mu=0 ).GRAPH J) Graph of SQR versus bit depth both with Companding (mu=255) and without Companding (mu=0). Where A=1 and bit depth are 2, 4, 8, 16, 32, 64, 128, 256. CONCLUSION: This lab was carried out to compact and quantize a speech signal. WeUsing pulse modulation technique, the analog signal is converted into digital signal. The process of quantization and compression of a signal is done on spreadsheets. To obtain a clear quantization signal-to-noise ratio, the number of samples should be increased. By increasing the sampling depth, the quantization error can be minimized. Through the compression process, quantization noise and distortion levels can be minimized. Compression improves response for low-amplitude signals.