| 摘要 |
PURPOSE:To make the size of a device small, to improve reliability and to reduce cost of inputting a four-channel digital audio signal to a channel mix section and synthesizing a 3-1 system four-channel program into a two-channel program. CONSTITUTION:A four-channel digital audio signal obtained via a parabolic antenna 50, a MUSE tuner 51, an LPF 52, an A/D converter 53, a MUSE audio digital signal processing section 54 is inputted to a channel mix section 59. Then prescribed equation arithmetic is implemented in the section 59 and the synthesized two-channel digital signal is converted into an analog signal by D/A converters 60, 61 and LPFs 62, 63 and outputted from audio signal output terminals 64, 65. That is, the circuit constitution is simplified by synthesizing the 3-1 system four-channel program into a two-channel program without converting the digital signal. Moreover, the channel circuit is realized by using a multiplier being the result of combination of a bit shifter and an adder to attain simple large scale integration for the circuit constitution, then the reliability is improved and the cost is reduced. |
