Abstract
This voltage control LC oscillator system controls the oscillator including the pressure (VCO), the digital phase-lock link (PLL), the monolithic integrated circuit (MCU) inserts the type system, high frequency power amplifier (RFAMP).
The system mainly uses MC145152, MC1648 and the initialization double model frequency divider B571 integration chip is a core, by monolithic integrated circuit 89C52 as well as the CPLD control module, the keyboard entry module, the liquid crystal display module, the programmable pressure controls the gain amplifier module, the output enlargement module and the oscillator power output instruction module constitution. This system VCO part used the sweeping change scope varactor to do vibrates the electric capacity, the frequency control scope is wide, when the input voltage changed from 0.5V to 8V, the output frequency may from 14MHz change to 39MHz, also could maintain the good linearity, vibrated the ring circuit to join the antivibration measure, the higher harmonic could be under the very good suppression, the output sine wave profile is good, the purity was high, distorts lowly, the scope was high also is stable. Because has used the numeral phase lock technique, causes VCO the frequency stability and the precision is extremely high, step-by-steps the value to be possible to establish (slightly in 1KHz to 1MHz in is willfully 1KHz), in order to the actual easy to operate and considered the topic request, this design step-by-steps the value to set is 100KHz.。
