Electronics & Communication / AM & Envelope Demodulation
FREE TO EXPLORE
LABORATORY 01 · ELECTRONICS & COMMUNICATION

Double-Sideband Full-Carrier Amplitude Modulation Index and Precision Diode Envelope Demodulation

Determine the modulation index (m) of a double-sideband full-carrier (DSB-FC) AM wave and evaluate the demodulated audio output voltage linearity across modulation depths from 10% to 100%. Explore interactive telecommunication simulation, RF analysis, and signal processing telemetry.

ANALOG MODULATION · DIGITAL BASEBAND · PASSBAND MODULATION · ANTENNAS & RF · OPTICAL FIBER · DSP

Your virtual electronics & communication engineering laboratory.

DEMODULATED AUDIO OUTPUT VOLTAGE V_DEMOD—
RF INSTRUMENTATION TELEMETRY

Ready to sample with Modulation Index = 0.5 ratio.

0.5 ratio
Excitation locked to low-phase-noise synthesized reference oscillator.

Adjust Modulation Index, then execute telecommunication RF/baseband acquisition.

Communication telemetry is sampled with calibrated high-precision instruments using 64-bit IEEE 754 precision buffers. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity modulation, channel, and spectral analysis.

Communication engineering assumptions and boundary limits

Channel modeled under additive white Gaussian noise (AWGN) and linear band-limited propagation. Harmonic distortion remains constrained below -45 dBc across all calibrated test points.

Laboratory apparatus & testing equipment.

AM & Envelope Demodulation Telecommunication Workstation

Provides regulated RF/baseband excitation, precision impedance-matched test fixtures, and low-noise interconnection for sideband power distribution, trapezoidal pattern analysis & diagonal clipping distortion.

6.5-Digit True-RMS Digital Multimeter (Keysight / Fluke)

Measures DC bias points, RMS carrier/signal voltages, and circuit node potentials with ±0.0035% baseline accuracy.

Four-Channel Digital Storage Oscilloscope (200 MHz, 2 GSa/s)

Captures high-frequency RF envelopes, baseband eye diagrams, constellation patterns, and transient responses for am & envelope demodulation.

Synthesized Vector RF Signal Generator (9 kHz – 3 GHz)

Delivers calibrated, low-phase-noise continuous-wave and modulated carrier signals to establish modulation index conditions.

High-Dynamic-Range RF Spectrum Analyzer (9 kHz – 3.6 GHz)

Quantifies fundamental harmonic amplitudes, carrier suppression ratios, sideband power distributions, and spurious emissions.

Matched 50-Ohm Coaxial Interconnects & Attenuator Set

Maintains uniform transmission line impedance, eliminates unwanted standing-wave reflections, and protects instrument front-ends.

FOLLOW THE METHOD

A reason behind every step.

Determine the modulation index (m) of a double-sideband full-carrier (DSB-FC) AM wave and evaluate the demodulated audio output voltage linearity across modulation depths from 10% to 100%. Standardized parameter settings: 0.1, 0.3, 0.5, 0.7, 0.9, 1.0 ratio.

  1. Apparatus Calibration & Ground Plane Verification: Inspect all coaxial BNC/SMA interconnects and verify 50-ohm characteristic termination. Power up all instruments and allow a 20-minute thermal settling period to stabilize crystal reference oscillators.
  2. Carrier & Modulating Signal Synthesis: Configure the synthesized RF signal generator and baseband source to the specified baseline parameters. Calibrate the modulation index using the precision digital multimeter and oscilloscope.
  3. Systematic Telemetry Acquisition & Setpoint Stepping: Increment the modulation index systematically across the experimental range (0.1 to 1.0 ratio), logging the resulting demodulated audio output voltage v_demod after signal settling.
  4. Frequency-Domain & Time-Domain Cross-Validation: Observe and photograph the corresponding waveform on the digital storage oscilloscope and verify the spectral distribution on the RF spectrum analyzer. Verify that harmonic distortion remains below -45 dBc.
  5. Repeatability & Hysteresis Verification: Execute both ascending and descending parameter sweeps across the device under test (DUT) to detect any thermal drift, detector non-linearity, or oscillator pulling.
  6. De-energization & Dataset Archival: Safely reduce RF excitation levels, save captured digital waveforms to non-volatile storage, export telemetry to the laboratory logbook, and power down all high-frequency instrumentation.
YOUR NOTEBOOK · 0 OBSERVATIONS

Turn measurements into telecommunication engineering insight.

See a complete example report ↗

Points are your recorded observations. The solid regression line validates AM & Envelope Demodulation mathematical scaling.

LINEAR REGRESSION FIT · y = mx + b
V_demod = 10.0000 · m
#Modulation Index m (ratio)Demodulated Audio Output Voltage V_demod (V)Modulation index mDemodulated audio voltage V_demod (V)

No readings yet. Execute a communication trial and record it.

CHECK YOUR UNDERSTANDING

Explain what the communication metrics mean.

Question 1: In the experimental investigation of AM & Envelope Demodulation, the primary dependent variable measured is:

Question 2: The mathematical relationship governing AM & Envelope Demodulation is modeled as:

Question 3: The target benchmark parameter derived from regression analysis is:

Question 4: Which instrument provides the most accurate visualization of spectral harmonics and carrier sidebands in the frequency domain?

THEORY AND ELECTROMAGNETIC CONTEXT

Electronics & Communication Engineering background & physical principles.

Determine the modulation index (m) of a double-sideband full-carrier (DSB-FC) AM wave and evaluate the demodulated audio output voltage linearity across modulation depths from 10% to 100%.

V_demod = 10.0000 · m

Communication systems rely on Fourier spectral decomposition, Shannon channel capacity, and electromagnetic propagation theory.