Synchronous radio-frequency FM signal generator using direct digital synthesizers.

Area of Science:

• Electrical Engineering
• Signal Processing
• Electronics

Background:

• Traditional RF-FM signal generation methods can be complex.
• Direct Digital Synthesis (DDS) offers precise frequency control.
• Phase modulation is crucial for advanced signal generation.

Purpose of the Study:

• To introduce a novel RF-FM signal generation technique.
• To develop and evaluate a prototype circuit for this method.
• To analyze the performance and characteristics of the generated RF-FM signals.

Main Methods:

• A voltage-controlled time delay modulates the phase of a reference sinusoidal signal.
• The phase-modulated signal clocks a DDS to produce an FM output.
• A second DDS, synchronously clocked, generates the modulating signal.
• All digital components are timed from a single sine wave oscillator.

Main Results:

• Generated carrier frequencies from 10 MHz to 70 MHz.
• Achieved modulation frequencies from 10 kHz to 300 kHz.
• Output signals exhibited phase-synchronized sidebands with integer harmonic frequency separation.
• Observed FM signal characteristics align with the Jacobi-Anger expansion.

Conclusions:

• The novel RF-FM signal generation method is functional and effective.
• The prototype circuit successfully produced FM signals with predictable characteristics.
• The results validate the theoretical predictions based on the Jacobi-Anger expansion.