Self Autonomous Oscillator: Design, Characterization, Modeling and Computer Analysis Based on NDR Devices PDF

Keywords

tunnel diode, R.F. signal, frequency, amplitude, oscillator

Abstract

Tunnel diode is still regarded as a very useful device in R.F signal processing systems because of its wider band width, temperature stability and lower noise, compared with other diodes. Analytical and experimental investigations and computer program technique has been carried out to control the frequency, amplitude, waveform and output power for different types of tunnel diodes. It is found that the amplitude, frequency and shape of oscillations depend mainly on the biasing condition, and diode-and circuit-parameters. The frequency and amplitude increase with increasing the bias voltage , reaching a maximum value followed by a plateau region, then they decrease at high bias values, which reflects the limits of the dynamic negative conductance of the tunnel diodes. Results of the sinusoidal oscillations are obtained using InSb tunnel diode having the frequency value of 2.35 MHz. On the other hand, output waveform becomes approximately square wave in case of GaAs samples having the frequency of 0.80 MHz is obtained. The experimental results of the relaxation oscillator show good agreement with the predicted characterization based on the analytical solution and a computer program technique.