| 摘要 |
PURPOSE:To reduce the 920kHz beat and to improve the differential gain and differential characteristics, by compensating the phase rotation of an intermediate frequency (IF) signal supplied to a multiplier circuit and approximating said phase rotation of the IF signal to the phase circuit characteristics of a signal supplied from a tuning/amplifying circuit. CONSTITUTION:The IF signal is supplied to the base of an emitter follower consisting of transistors TR13, 14, etc. to receive an impedance conversion. Then the IF signal is supplied to a differential amplifier consiting of TR17 and 18, a constant current source 21, etc. The collectors of TR17 and 18 are connected to the collectors of TR32 and 34 as well as TR33 and 35 with their emitters connected via resistances 44 and 45. These collectors reach a power supply 27 respectively via load resistances 36 and 37. The resistances 44 and 45 function to increase the collector resistance of TR17 and 18. The phase characteristics of the IF signal can be compensated by making use of Miller capacity of TR17 and 18 and the parasitic stray capacity. |
