Let’s suppose the message x(t) is an analog signal shown in the figure below.
a) Draw the block diagrams of the system which converts the analog message signal x(t) to a pulse modulated signal.
b) Draw the sampled signal with the sampling frequency fs=2khz
c) Carry out the quantization process with the quantization level q=2^n = 8
d) Generate the PCM code words.
e) Draw the pulse modulated signal in the form of Bipolar NRZ (non-return to zero)
using the first eight digits of the code words generated in (d).
To answer these questions, we need to follow several steps. Let's go through them one by one:
a) Block Diagrams for Converting Analog Signal to Pulse Modulated Signal:
To convert an analog signal x(t) to a pulse modulated signal, we generally use three main components: a sampler, a quantizer, and a pulse modulator.
1. Sampler: The sampler samples the analog signal at regular intervals to obtain discrete samples. In this case, the signal should be sampled with a frequency of 2kHz, which means sampling every 1/fs seconds.
2. Quantizer: The quantizer assigns specific levels to each sample based on a predetermined quantization step size. In this case, the quantization level is q=8, which means we have 2^3 = 8 quantization levels.
3. Pulse Modulator: The pulse modulator converts the quantized samples into a pulse modulated signal. The specific pulse modulator will depend on the type of modulation required (e.g., pulse amplitude modulation (PAM), pulse width modulation (PWM), pulse position modulation (PPM)).
b) Sampled Signal:
To draw the sampled signal, we need to plot the discrete samples obtained from the sampler. Each sample value should be plotted at the corresponding sampling time points (every 1/fs seconds).
c) Quantization Process:
To carry out the quantization process, we need to assign a quantization level to each sample obtained from the sampler. The quantization level q is given as 2^n = 8, which means n=3. This means we need to divide the range of sample values into 8 equally spaced levels.
d) PCM Code Words:
PCM (Pulse Code Modulation) involves encoding each quantized sample into a binary code word. The number of bits in the code word is determined based on the number of quantization levels. In this case, since we have 8 quantization levels, we need 3 bits to represent each level. Therefore, each sample will be represented by a 3-bit code word.
e) Pulse Modulated Signal (Bipolar NRZ):
To draw the pulse modulated signal in the form of Bipolar NRZ (non-return to zero) using the first eight digits of the code words generated in (d), we need to plot a sequence of pulses based on the binary values of the code words. In Bipolar NRZ, the pulse level can be either positive or negative, representing the binary bit values.
Please note that without having a specific analog signal figure or additional information, we can only provide a general explanation of the process. It would be helpful to have more details or the actual analog signal figure to provide a more accurate answer.