Simulation of ASK, FSK, and PSK using MATLAB Simulink (with Online Simulator)

Simulation of Amplitude Shift Keying (ASK) using MATLAB Simulink

In Simulink, we pick different components/elements from MATLAB Simulink Library. Then we connect the components and perform a particular operation.

Result

A sine wave source, a pulse generator, a product block, a mux, and a scope are shown in the diagram above. The pulse generator generates the '1' and '0' bit sequences. Sine wave sources produce a specific amplitude and frequency. The scope displays the modulated signal as well as the original bit sequence created by the pulse generator. Mux is a tool for displaying both modulated and unmodulated signals at the same time.

The result section shows that binary '1' is modulated by a certain sine wave amplitude of 1 Volt, and binary '0' is modulated by zero amplitude.

Simulation of Frequency Shift Keying (FSK) using MATLAB Simulink

Result

The diagram above shows two sine wave sources, a pulse generator, a switch, a mux, and a scope. The pulse generator generates the '1' and '0' bit sequences. Two different frequencies are provided by sine wave sources. The result section shows that binary '1' is modulated at a higher frequency than binary '0'.

Simulation of Phase Shift Keying (PSK) using MATLAB Simulink

Result

In the result section, binary '1' is modulated with a 180-degree phase shift (corrected), whereas binary '0' is modulated with the original 0-degree phase.

Simulator for Binary ASK Modulation

Message Bits

Carrier Freq (Hz)

Sampling Rate (Hz)

Simulator for Binary FSK Modulation

Input Bits

Freq '1' (Hz)

Freq '0' (Hz)

Sampling (Hz)

Simulator for Binary PSK Modulation

Input Bits

Carrier Freq (Hz)

Sampling (Hz)

Mathematical Background

1. Amplitude Shift Keying (ASK)

The signal is represented by changing the amplitude of the carrier wave. For Binary ASK:

$$s(t) = \begin{cases} A \cos(2\pi f_c t) & \text{for bit 1} \\ 0 & \text{for bit 0} \end{cases}$$

2. Frequency Shift Keying (FSK)

The frequency of the carrier is shifted between two discrete values ($f_0$ and $f_1$):

$$s(t) = \begin{cases} \cos(2\pi f_1 t) & \text{for bit 1} \\ \cos(2\pi f_0 t) & \text{for bit 0} \end{cases}$$

3. Phase Shift Keying (PSK)

The phase of the carrier is shifted by 180° ($\pi$ radians) to represent different bits:

$$s(t) = \begin{cases} \cos(2\pi f_c t) & \text{for bit 1 (0 rad)} \\ \cos(2\pi f_c t + \pi) & \text{for bit 0 ($\pi$ rad)} \end{cases}$$

ASK, FSK, PSK Constellation Diagrams Simulation →

ASK, FSK, PSK BER vs SNR Simulation →

Search This Blog