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Online Simulator for ASK, FSK, and PSK


Interactive Digital Signal Processing (DSP) Tutorial and Simulator for ASK, FSK, and BPSK modulation techniques.
Try our new Digital Signal Processing Simulator!   •   Interactive ASK, FSK, and BPSK tools updated for 2025.

Digital Modulation Visualizer: ASK, FSK, & BPSK Simulator

Learn and visualize binary modulation techniques (ASK, FSK, BPSK) in real-time with adjustable carrier and sampling parameters. Perfect for DSP students and engineers.

๐Ÿ“ก ASK Simulator ๐Ÿ“ถ FSK Simulator ๐ŸŽš️ BPSK Simulator ๐Ÿ“š More Topics
1. ASK (Amplitude Shift Keying) Simulator Digital
2. FSK (Frequency Shift Keying) Simulator Digital
3. BPSK (Binary Phase Shift Keying) Simulator Phase

Modulation Workflow & Mathematics Theory

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}$$

⚠️ Simulation Constraints & Rules

To ensure a valid and visually clear simulation, the following digital signal processing (DSP) rules must be followed:

  • • Nyquist Criteria: The Sampling Frequency ($f_s$) must be at least twice the Carrier Frequency ($2 \times f_c$). For a smooth visual curve, $f_s \ge 10 \times f_c$ is recommended.
  • • Carrier vs. Message: The Carrier Frequency should be much higher than the Bit Rate ($f_c \gg R_b$). In these simulators, Bit Duration is fixed at 1s ($R_b = 1$ bps).
  • • Aliasing Warning: If $f_s < 2f_c$, the output waveform will suffer from aliasing, appearing as a lower-frequency distorted wave.
  • • Phase Continuity: These simulators use "Sudden Phase Transition" (Non-coherent) modeling for simplicity.

๐Ÿงช Experiment for Students:

"Try setting the Carrier Frequency to 50Hz and the Sampling Frequency to 40Hz in the ASK simulator. Observe the Aliasing Effect—the waveform will no longer resemble a sine wave because the Nyquist criteria is violated."

Try Other Interactive Online Simulators

๐Ÿ“ป Analog Modulations

๐Ÿ”ขQPSK

๐Ÿ”ข M-ary QAM & PSK Modulations

๐Ÿ”ข Continuous Phase Modulations

๐Ÿ”ข Doppler Spectrum

๐Ÿ”ข OFDM

๐Ÿ”ข Wiener Filter

MATLAB Codes for Modulation

View MATLAB Codes for ASK, FSK, and PSK =>

Modulation FAQ & Help

Why is BPSK more noise-resistant than ASK?

BPSK relies on phase shifts (180 degrees) rather than amplitude. Since noise typically affects the amplitude of a signal, BPSK remains more recognizable to a receiver even in high-interference environments.

What is the Nyquist rate in these simulations?

The Nyquist rate requires the sampling frequency to be at least twice the highest frequency component. In our simulator, if your Carrier is 10Hz, your Sampling must be at least 20Hz.

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