SELF AUTONOMOUS OSCILLATOR - DESIGN, CHARACTERIZATION, MODELING AND COMPUTER-ANALYSIS BASED ON NDR DEVICES

Tunnel diode is still regarded as a very useful device in R.F signal p rocessing systems because of its wider band width, temperature stabili ty and lower noise, compared with other diodes. Analytical and experim ental investigations and computer program technique has been carried o ut to control the frequency, amplitude, waveform and output power for different types of tunnel diodes. It is found that the amplitude, freq uency and shape of oscillations depend mainly on the biasing condition , and diode-and circuit-parameters. The frequency and amplitude increa se with increasing the bias voltage, reaching a maximum value followed by a plateau region, then they decrease at high bias values, which re flects the limits of the dynamic negative conductance of the tunnel di odes. Results of the sinusoidal oscillations are obtained using InSb t unnel diode having the frequency value of 2.35 MHz. On the other hand, output waveform becomes approximately square wave in case of GaAs sam ples having the frequency of 0.80 MHz is obtained. The experimental re sults of the relaxation oscillator show good agreement with the predic ted characterization based on the analytical solution and a computer p rogram technique.