Surround audio apparatus

• US 5,257,313 A
• Filed: 07/03/1991
• Issued: 10/26/1993
• Est. Priority Date: 07/09/1990
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Sato, Kazuhiro, Fujishita, Kaneaki
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US07/725,454
• Time in Patent Office: 846 Days
• Field of Search: 381/18, 381/22, 381/63
• US Class Current: 381/18
• CPC Class Codes: H03G 5/005 of digital signals
• CPC Class Codes: H04S 3/02 of the matrix type, i.e. in which input signals are combined algebraically, e.g. after having been phase shifted with respect to each other
• CPC Class Codes: H04S 7/305 Electronic adaptation of stereophonic audio signals to reverberation of the listening space H04S7/301 takes precedence
• CPC Class Codes: H04S 7/307 Frequency adjustment, e.g. tone control H04S7/301 takes precedence

Abstract

A surround audio apparatus is comprised of an input terminal to which a stereo audio signal encoded for surround reproduction is supplied, an analog-to-digital converter for converting the stereo audio signal supplied to the input terminal into a digital audio signal, a digital signal processor for decoding the digital audio signal converted by the analog-to-digital converter in a surround stereo reproduction fashion to output a digital surround signal, a digital-to-analog converter for converting the digital surround signal from the digital signal processor into an analog surround signal, and an output terminal from which the analog surround signal from the digital-to-analog converter is delivered.

Claims

1. A surround audio apparatus comprising:

input terminals to which a plurality of digital audio signals encoded for surround reproduction are supplied;

a first digital signal processor for generating a test tone signal and for adjusting level balances between selected ones of said plurality of digital audio signals;

a switching circuit connected to said input terminals and said first digital signal processor for supplying selected ones of said plurality of digital audio signals to said first digital signal processor;

a second digital signal processor connected to said first digital signal processor for decoding an output signal of said first digital signal processor in a surround stereo reproduction fashion and producing a feedback signal fed to said first digital signal processor for adjusting said level balances between selected ones of said plurality of digital signals;

a third digital signal processor connected to said second digital signal processor for processing an output signal of said second digital signal processor so as to create or correct a sound field;

digital-to-analog converter means connected to said third digital signal processor for converting an output signal from said third digital signal processor into an analog audio signal; and

an output terminal connected to said digital-to-analog converter from which said analog audio signal is delivered.

2. A surround audio apparatus comprising:

input terminals to which a plurality of digital audio signals encoded for surround reproduction are supplied;

first digital signal processor for generating a test tone signal, adjusting balance of levels between selected ones of said plurality of digital audio signals and correcting a dynamic range;

a switching circuit connected to said input terminals and said first digital signal processor for selectively supplying two of said plurality of digital audio signals to said first digital signal processor;

second digital signal processor means including a plurality of digital signal processors connected to said first digital signal processor means for decoding output signals from said first digital signal processor in a surround stereo reproduction fashion and producing a feedback signal fed to said first digital signal processor means for said adjusting balance of levels thereby;

third digital signal processor means connected to said second digital signal processor means for performing parametric equalization processing;

fourth digital signal processor means including a plurality of parallel connected digital signal processors each connected to said third digital signal processor means for performing a reverberation processing;

a digital-to-analog converter connected to said fourth digital signal processor means; and

a pair of output terminals from which analog signals from said digital-to-analog converter are respectively delivered, wherein output signals of said second digital signal processor means are supplied in series to said third and fourth digital signal processor means, thereby being converted to equalizer-processed and reverberation-processed digital signals and said digital signals are supplied to said digital-to-analog converter.