Active Preselection Filter Techniques for Adjacent Channel Interference Suppression at UHF

The development of a Q multiplier device which operates in the UHF region is described. With this device, preselection bandwidths representing a Q of approximately 7,000 were achieved at 300 MHz. The high Q values are obtained with a relatively compact device. Operational results illustrate the application of this device for improved filtering of closely spaced signals.