Differential sampling relative to a Josephson waveform, the ac quantum voltmeter (ac-QVM), has been established as the most accurate method for measuring signals below 1 kHz with an uncertainty of 1 part in 10⁸ (k = 1) for 1V at 250Hz. Commercial ac-QVMs provide accuracies of about 1 part in 10⁶ up to frequencies of 2 kHz. Here we present a new sub-sampling technique to extend the frequency range of an ac-QVM up to 100 kHz. The measurement results at 1V RMS amplitude agree well within 5 V V⁻¹ (k = 1) with the nominal voltage values for all frequencies from 500Hz to 100 kHz. Two different analogue-to-digital converters are compared, sampling techniques, error sources and corrections as well as detailed uncertainty estimations are discussed.

相对于约瑟夫森波形的差分采样，交流量子电压表 (ac-QVM) 已被确立为测量 1 kHz 以下信号的最准确方法，不确定度为 10 ⁸ ( k = 1)的 1 分之一( k = 1)，250Hz 时为 1V . 商用 ac-QVM 在高达 2 kHz 的频率下提供大约 10 ^{6 分之一的}精度。在这里，我们提出了一种新的子采样技术，可将 ac-QVM 的频率范围扩展到 100 kHz。1V RMS 幅度下的测量结果在 5 VV ^-1 ( k= 1) 具有从 500Hz 到 100kHz 的所有频率的标称电压值。比较了两种不同的模数转换器，讨论了采样技术、误差源和校正以及详细的不确定性估计。