Superheterodyne Receiver Online Simulator

Superheterodyne Receiver Simulator

Simulation Controls

Message Frequency (Hz):
Carrier Frequency (Hz):
Intermediate Frequency (Hz):
Sampling Frequency (Hz):
Simulation Duration (s):

Signal Plots

Numerical Values (first 10 samples)

Superheterodyne Receiver Workflow

The superheterodyne receiver converts a received RF signal to an intermediate frequency (IF) to simplify filtering and amplification, and finally recovers the original message signal.

Steps:

1. Input Message Signal: A low-frequency signal m(t) (e.g., sine wave).
2. RF Modulation (AM): The message modulates the carrier with amplitude modulation: RF(t) = [1 + K_a * m(t)] * cos(2π f_c t)
3. Mixing with Local Oscillator (LO): The RF signal is multiplied by a local oscillator LO(t) = cos(2π f_LO t) to produce: IF(t) = RF(t) * LO(t)
4. Intermediate Frequency Filtering: A low-pass filter extracts the lower-frequency components (IF) while removing high-frequency products.
5. Demodulation (Envelope Detection): Rectification (absolute value) followed by low-pass filtering extracts the original message m(t).

Key Equations:

• AM RF Signal: RF(t) = [1 + K_a * m(t)] * cos(2π f_c t)
• Local Oscillator: LO(t) = cos(2π f_LO t)
• Mixed Signal (IF): IF(t) = RF(t) * LO(t) = 0.5 * [1 + K_a * m(t)] * [cos(2π(f_c+f_LO)t) + cos(2π(f_c-f_LO)t)]
• Low-pass filter removes high-frequency term cos(2π(f_c+f_LO)t), leaving: 0.5 * [1 + K_a * m(t)] * cos(2π(f_c-f_LO)t)
• Envelope detector: Recovered m(t) ≈ LPF(|Filtered IF|)