奈奎斯特频率

CCD相机在系统奈奎斯特频率处的调制传递函数

Modulation Transfer Function of CCD Camera at Nyquist Frequency

对振动下系统MTF与静态情况下进行了实验比较，结果表明在相同奈奎斯特频率处下降0.3左右，与仿真结果一致。

Vibrational MTF is compared with that under static condition , and the results are consistent with simulation curve with a30 % decrease at the Nyquist frequency .

利用输入信号频率与采样频率互为质数的特点，可使并行交替式ADC系统对直流和奈奎斯特频率的输入信号幅度分辨力都能提高。

According to the characteristics of output signal spectra with offset dither , the resolution of time-interleaved ADC to the input signal with a frequency range from DC to Nyquist frequency can be improved by using low pass filters .

介绍了一种高性能CMOS采样/保持电路。该电路在3V电源电压下，60MHz采样频率时，输入直到奈奎斯特频率仍能够达到90dB的最大信号谐波比（SFDR）和80dB的信噪比（SNR）。

A high performance CMOS sample / hold circuit is presented , which achieves 90-dB spurious-free dynamic range and 80-dB signal-to-noise ratio over Nyquist band in 60 MHz sampling frequency at 3 V supply .

低字率、高采样频率的数字调制信号被转换成高字率、奈奎斯特频率采样的信号。

It transforms the digitally modulated signal from short words occurring at high sampling rate to longer words at Nyquist rate .

借助数字内插波束形成方法，采样率只要求等于或略高于奈奎斯特频率，从而大大降低了对设备的性能需求。

The method of digital interpolation beam-forming , demanding the sample frequency be equal to or a bit higher than Nyquist frequency .

为了保证采样高于奈奎斯特频率的输入信号时的线性度，输入端依然采用了采样/保持电路。

A front-end sample and hold circuit is maintained to ensure the performance when the frequency of the input signal is higher than the nyquist frequency .

在高采样频率条件下（高于奈奎斯特频率），背景噪声是有色的。

With low sampling frequency ( below the Nyquist frequency ) the background noise may be considered to be white because of aliasing , while it is colored with high sampling frequency ( above the Nyquist frequency ) .

压缩感知以远低于奈奎斯特频率进行采样，采用非自适应线性投影来保持信号的原始结构，通过数值最优化问题准确重构原始信号。

In the compressed sensing theory sampling rate is well below the Nyquist frequency , using non-adaptive linear projection to maintain the original structure of the signal , and reconstructing the original signal accurately by solving optimization problem .

在磁共振成像中，为了减少扫描时间通常使用欠采样方式，但欠采样方式不满足奈奎斯特采样频率，从而引起混叠伪影。

In MRI , subsampling is used to reduce data scanning time which does not satisfy the Nyquist sampling frequency and result in image aliasing .

稀疏表示与压缩感知理论指出，稀疏信号可通过一组线性测量值重建得到原信号，在获得测量值时，采样率可低于奈奎斯特采样频率。

The theory of sparse representation and compressive sensing can be used for the reconstruct of sparse or compressible signals from a small set of linear measurements .

该理论方法已得到了实际应用，从获得的遥感图像达到的分辨力、奈奎斯特（Nyquist）频率处的传递函数、信噪比和平均灰度层次均充分证明了该研究结果的正确性。

This total solution was applied to SORS system field test and has been confirmed to be very accurate based on the resolution , transfer function at Nyquist frequency , signal-to-noise ratio and average gray scale of the captured images .

传统的信号处理是以奈奎斯特采样定理为基础的，信号通常先采样后压缩，而且必须以高于奈奎斯特频率的速率对信号进行采样和处理。

Traditional signal processing is based on the Nyquist sampling theorem , in which the signal is usually sampled firstly and then compressed , and the signal sampling and processing rate must be higher than the Nyquist frequency .