ELECTRONIC COMMUNICATION SYSTEMS

Presenter Damion Lawrence, M.Sc., B.Ed

A communication system block diagram.

Linear addition of two sine waves.

AM waveform under varying intelligence signal (ei) conditions.

Nonlinear mixing.

Percentage modulation determination.

Modulation by a band of intelligence

frequencies.

Simple transistor modulator.

(a) High- and (b) low-level modulation.

Simple AM transmitter block diagram.

Class D citizens band transmitter.

Signal injection.

Signal tracing.

Trapezoidal pattern connection scheme and displays.

Comparing input and output signals.

The Multisim component view for the simple transistor amplitude modulator

circuit.

The Multisim oscilloscope control panel.

Simple radio receiver block diagram.

Superheterodyne receiver block diagram.

Frequency conversion process.

Image frequency not a problem.

Troubleshooting a self-excited mixer.

Diode detector.

An AM diode detector circuit as implemented with Electronics WorkbenchTM Multisim.

Oscilloscope output traces from the diode detector.

A synchronous AM detector circuit as implemented in Electronics WorkbenchTM Multisim.

The waveforms obtained from TP1 and TP2 for the synchronous AM detector

AM broadcast superheterodyne receiver.

FM representation.

Varactor diode modulator.

Crosby direct FM transmitter.

PLL FM transmitter block diagram.

A frequency-modulation circuit using a voltage-controlled oscillator, as implemented in an Electronics WorkbenchTM

Multisim circuit.

The oscilloscope display of the 10-kHz triangle wave and the output of the VCO.

FM receiver block diagram.

Slope detection.

Typical FM receiver.

An implementation of an FM receiver using Multisim.

The frequency plot of the bandpass filter.