| 摘要 |
PURPOSE:To realize a privacy telephone in good condition with no use of a BPF nor an output filter, by obtaining a signal by dividing an input voice signal in band and replacing the result in order with use of plural oscillators, phase shifters, frequency converters, etc. CONSTITUTION:The output at one side of an adder 414 transmits the signal obtained by shifting 418 the output of an oscillator 416 by 90 deg. in phase to a frequency oscillator 418 in the form of a local oscillating signal and at the same time is transmitted to an adder 424 through an LPF419 after applying a frequency conversion 420 by an oscillator 421. While the other output of the adder 414 is applied with frequency conversion 427 and is supplied to a frequency converter 430 via an LPF429. The output of the oscillator 421 is applied to the converter 430 after shifting 423 by 90 deg. in phase, and the output of the converter 430 is fed to the adder 424. Thus the outputs of converters 430 and 420 are added together and delivered through a terminal 425. |
