HIGH-FREQUENCY TUNABLE FILTER

摘要

The filter comprises first and second oscillating circuits tuned by voltage-controlled varicap diodes. It comprises varicap diodes coupled between the first and second varicap diodes. The varicap diodes for the tuning of the oscillating circuits and the coupling varicap diodes between the first oscillating circuit and the second oscillating circuit are controlled by a same control voltage to obtain the tuning of the filter to its working frequency and the critical coupling of the two oscillating circuits. Application: portable radio transceivers. FIGURE 1