MIDDLE FREQUENCY GENERATOR

摘要

PURPOSE: A middle frequency generator is provided which removes the higher harmonics of a carrier wave by using differential amplifier. CONSTITUTION: The carrier wave in the modulation signal causes signal degradation. This device removes the carrier wave by adjusting data voltage. The differential amplifier (210) decides the resistance value with variable resistor (VR1) to adjust data voltage. And the differential amplifier (220) adjusts the bias voltage in the carrier wave CARRIER_IN, and removes the higher harmonics. The resistance value of the variable resistor (VR2) is adjusted to send the bias voltage level in the carrier wave CARRIER_IN to the reversal input terminal. The differential amplifier (220) amplifies and outputs only pure carrier wave CARRIER_IN signal by subtracting bios voltage level from the carrier wave. VR2 resistance value decides the voltage level sent to the reversal terminal of differential amplifier (220). Finally by using a differential amplifier, the carrier wave of higher harmonics is removed.