Signal selecting circuit and program

Abstract

A signal selecting circuit is disclosed which outputs a first and a second digital signals by converting a first and a second analog signals into digital signals, the first and the second analog signals being the same or different signals selected from a plurality of analog signals, the signal selecting circuit comprising: an analog signal selection circuit that, based on an analog selection signal, selects the first and the second analog signals from the plurality of analog signals; a first AD converter that converts the first analog signal outputted from the analog signal selection circuit into a third digital signal to output the third digital signal; a second AD converter that converts the second analog signal outputted from the analog signal selection circuit into a fourth digital signal to output the fourth digital signal; a digital signal selection circuit that, based on a digital signal, selectively outputs one or both of the third and the fourth digital signals as the first and the second digital signals; and a control circuit that, based on an output selection signal for selecting the first and the second digital signals, outputs the analog selection signal and the digital selection signal. Thereby, when a certain outputted signal is swithing, no noise is generated in the outputted signals which are not swithed.

Description

technical field [0001] The invention relates to a signal selection circuit and program. Background technique [0002] In recent years, in car audio (car audio) devices, music or sound from different sound sources is output to speakers on the front seat side and speakers on the rear seat side (for example, Patent Document 1). Such car audio systems often employ an analog selector for selecting a sound source to be output to speakers on the front seat side and speakers on the rear seat side from a plurality of sound sources (analog signals) such as CDs, MDs, and radios. [0003] 14 is a diagram showing a general configuration example of an analog selector for selecting a sound source to be output to a speaker on the front seat side and a speaker on the rear seat side. The analog selector 201 is used to select a sound source output to the speakers on the front seat side, and includes switches 211 and 212 , resistors 213 to 215 , and an operational amplifier 216 . In addition,...

AI Technical Summary

Problems solved by technology

At this time, switching noise occurs due to the switch 231 being turned on, but this noise also propagates to the switch 211 side.

Therefore, if the same sound source as the front seat side is selected on the rear seat side, noise will be generated in the analog output 1 output to the front seat side speaker even if the sound source is not switched on the front seat side.

Similarly, when the same sound source is selected on the front seat side as on the rear seat side, noise is generated in the analog output 2 output to the rear seat side speaker even if the sound source is not switched on the rear seat side.

Images