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.

📡 ASK Simulator 📶 FSK Simulator 🎚️ BPSK Simulator 📚 More Topics

ASK Modulator FSK Modulator BPSK Modulator More Topics

1. ASK (Amplitude Shift Keying) Simulator Digital

Message Bits

Carrier Freq (Hz)

Sampling Rate (Hz)

2. FSK (Frequency Shift Keying) Simulator Digital

Input Bits

Freq '1' (Hz)

Freq '0' (Hz)

Sampling (Hz)

3. BPSK (Binary Phase Shift Keying) Simulator Phase

Bitstream

Carrier Freq (Hz)

Sampling (Hz)

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.

🧪 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

📻 Analog Modulations

• Amplitude Modulation (AM)
• Frequency Modulation (FM)
• Phase Modulation (PM)

🔢QPSK

• QPSK Signal Genaration (with Simulator)
• QPSK Constellation Simulation

🔢 M-ary QAM & PSK Modulations

• QAM Constellation (4, 16, 64, 256)
• M-ary PSK Constellation Diagrams
• Interactive BER vs SNR Simulator for m-ary PSK & QAM
• Advanced M-ary Modulation Simulator: Constellation, min dist, Efficiency, SER, EVM (RMS)
• Passband QAM Signal Generation

🔢 Continuous Phase Modulations

• MSK (minimum shift keying)
• GMSK (gaussian minimum shift keying)
• BPSK vs MSK (phase comparison)
• BPSK vs MSK vs GMSK (Spectral and Phase comparison)

🔢 Doppler Spectrum

• Interactive Doppler Spectrum Simulator

🔢 OFDM

• OFDM with BPSK Simulator
• OFDM BER vs SNR Simulation

🔢 Wiener Filter

• Interactive Medical Imaging Simulator: Wiener Filter Denoising

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.

Return to DSP Simulations Main Page →