| 摘要 |
PROBLEM TO BE SOLVED: To provide a tuner with reduced phase noises of a local oscillator in a frequency conversion circuit thereby attaining improvement in receiving quality, local leakage, oscillation stability and economy. SOLUTION: In a local oscillator in a frequency conversion circuit, the base of one transistor 5-1 differential pair is connected to one end of a resonance circuit 41 through a feedback capacitor 14 and also, the collector of the other transistor 5-2 differential pair is connected through a feedback capacitor 15. On the other hand, only the base of the transistor 5-2 is connected to the other end of the circuit 41 through a feedback capacitor 17. Consequently, a differential amplifier circuit 42 consisting of the transistors 5-1 and 5-2 is connected to the circuit 41. |
