Method and apparatus for evaluating transmission impairments of multiplexing converter
A method and an apparatus for evaluating transmission impairments of a multiplexing converter. According to the method, impairments of a multiplexing converter are equivalent to the equivalent multiplicative noise and the equivalent additive noise, so as to allow evaluation of transmission impairments of the multiplexing converter, thereby to allow evaluation of the performance of a communication system. The multiplexing converter is a multiplexing analog-to-digital converter, or a multiplexing digital-to-analog converter. According to the present application, impairments of a multiplexing converter can be evaluated accurately, the performance evaluation of a communication system using the multiplexing converter is given, without being affected by an amplitude, a modulation format and a transmission rate of an input signal.
1 . An apparatus for evaluating transmission impairments of a multiplexing converter, the apparatus comprising:
an evaluation unit configured to:
measure equivalent multiplicative noise and equivalent additive noise of a multiplexing converter, the multiplexing converter being a multiplexing analog-to-digital converter, or a multiplexing digital-to-analog converter; and
evaluate transmission impairments of the multiplexing converter using the equivalent multiplicative noise and the equivalent additive noise.
2 . The apparatus according to claim 1 , wherein the evaluation unit comprises:
a measurement unit, configured to measure, at a receiving end, a power of single tone excitation signals with different amplitudes and at least one frequency, transmitted by a transmitting end, and a power of total harmonic distortion and noise; and
a fitting unit, configured to linearly fit the power of the single tone excitation signals and the power of total harmonic distortion and noise to obtain a fitting formula, and an intercept of the fitting formula being used as a power of additive noise for measuring the equivalent additive noise and a slope of the fitting formula being used as a variance of multiplicative noise for measuring the equivalent multiplicative noise.
3 . The apparatus according to claim 1 , wherein the evaluation unit comprises:
a measurement unit, configured to measure, at a receiving end, a power of a single tone excitation signal with a single amplitude and at least one frequency, transmitted by a transmitting end, a power of total harmonic distortion and noise, a power of an all-zero excitation signal transmitted by the transmitting end being used as a power of additive noise for measuring the equivalent additive noise, and a power obtained by subtracting the power of the all-zero excitation signal from the power of total harmonic distortion and noise and dividing by the power of the single tone excitation signal being used as a variance of multiplicative noise for measuring the equivalent multiplicative noise.
4 . The apparatus according to claim 2 , wherein,
the power of the single tone excitation signals and the power of total harmonic distortion and noise are respectively a power measured at one frequency, or an average power measured at multiple single tone excitation signals with different frequencies; and
the average power is obtained by equal-weighted or non-equal-weighted averaging of powers measured at the multiple single tone excitation signals with different frequencies.
5 . An apparatus for communication system performance, the apparatus, the apparatus comprising:
a measurement unit, configured to measure equivalent multiplicative noise and equivalent additive noise of a communication system, the communication system comprising a multiplexing analog-to-digital converter and a multiplexing digital-to-analog converter;
a calculation unit, configured to multiply an input signal of the communication system by the equivalent multiplicative noise, then plus the equivalent additive noise, as an output signal of the communication system; and
an estimation unit, configured to estimate performance of the communication system based on the output signal.
6 . The apparatus according to claim 5 , wherein the input signal of the communication system is a signal that has passed through a linear filter.
7 . The apparatus according to claim 5 , wherein
the equivalent additive noise is additive white Gaussian noise with a locked power; and
the equivalent multiplicative noise is a random Gaussian distribution noise with a locked variance.
8 . The apparatus according to claim 5 , wherein the measurement unit is configured to measure, at a receiving end, a power of single tone excitation signals with different amplitudes and at least one frequency, transmitted by a transmitting end, and a power of total harmonic distortion and noise;
wherein the measurement unit comprises:
a fitting unit, configured to linearly fit the power of the single tone excitation signals and the power of total harmonic distortion and noise to obtain a fitting formula, an intercept of the fitting formula being used as a power of additive noise for measuring the equivalent additive noise and a slope of the fitting formula being used as a variance of multiplicative noise for measuring the equivalent multiplicative noise.
9 . The apparatus according to claim 5 , wherein the measurement unit is configured to measure, at a receiving end, a power of a single tone excitation signal with a single amplitude and at least one frequency, transmitted by a transmitting end, a power of total harmonic distortion and noise, a power of an all-zero excitation signal transmitted by the transmitting end being used as a power of additive noise for measuring the equivalent additive noise, and a power obtained by subtracting the power of the all-zero excitation signal from the power of total harmonic distortion and noise and dividing by the power of the single tone excitation signal being used as a variance of multiplicative noise for measuring the equivalent multiplicative noise.
10 . The apparatus according to claim 8 , wherein
the power of the single tone excitation signal and the power of total harmonic distortion and noise are respectively a power measured at one frequency, or an average power measured at multiple single tone excitation signals with different frequencies; and
the average power is obtained by equal-weighted or non-equal-weighted averaging of powers measured at the multiple single tone excitation signals with different frequencies.