| 摘要 |
Method and system for measuring the transmission quality of an audio transmission system, an input signal (X) being entered into the system, resulting in an output signal (Y), output by the system, both signals, the input signal and the output signal, being mutually processed, the method comprising that the output signal and/or the input signal of the system under test are scaled in a way that small deviations of the power are compensated, while larger deviations are compensated partially, dependent on the power ratio. A compensation ratio F is calculated from the power representations PX and PY resp. of said input signal (X) and output signal (Y), being equal to the ratio PX/PY. A clipped ratio C is calculated, C being equal to a first clipping value mm for F<mm, or C being equal to a second clipping value MM for F>MM, or otherwise C being equal to F. A softscale ratio S is calculated from a first scaling factor m and a second scaling factor M, with mm < m≤1 and MM > M≥1, S being equal to C<a> + C - C(m)<a-1> for C < m, 'a' being a first tuning parameter being set to a value > 0 and < 1, or S being equal to C<a> + C - C(M) <a-1> for C > M, or otherwise S being equal to C. An artificial reference speech signal may be created, for which the noise levels as present in the original input speech signal are lowered by a scaling factor that depends on the local level of the noise in this input. <IMAGE>
|
