| 摘要 |
An apparatus for encoding a plurality of n digital information signals is provided with at least a first, second and third input terminal (1,2,3) for receiving a first, a second and a third digital information signal (L,R,C). A matrixing unit (10) is provided for generating a first and a second digital composite signal (L0,R0) from the at least the first, second and third digital information signals. First and second data compression means (22.1,22.2) are provided for data compressing the first and second composite signal (L0,R0) so as to obtain first and second data reduced digital composite signals. A first selection unit (16) is provided for selecting at least one information signal from said plurality of n information signals so as to obtain at least a first auxiliary signal (AUX1). At least a third data compression means (22.3) is present for data compressing the at least first auxiliary signal so as to obtain a first data reduced auxiliary signal. A formatting unit (24) is present for combining the first and second data reduced composite signals and the at least first data reduced auxiliary signal into a transmission signal suitable for transmission via a transmission medium. The apparatus further comprises at least first, second and third masked threshold determining means (26.1,26.3,26.4) for determining first (mtL), second (mtC) and third (mtL0) masked thresholds respectively. A second selection unit (28.1) is provided for deriving one masked threshold from at least the first (mtL) and third (mtL0) masked threshold so as to obtain a first selected masked threshold (mt1). Preferably, said first selected masked threshold is the smallest of the said at least first (mtL) and third (mtL0) masked thresholds. |
