Ben-Romdhane Manel, Maalej Asma, Tlili Mariam, Rebai Chiheb, Rivet François, Dallet Dominique
COSIM Research Laboratory, SUP'COM, University of Carthage, Cité Technologique des Communications, 2083 El Ghazala, Ariana Tunisia.
LIP6, CNRS, Sorbonne University, 75005 Paris, France.
Arab J Sci Eng. 2020;45(8):6361-6387. doi: 10.1007/s13369-020-04483-w. Epub 2020 Mar 31.
The long-term monitoring of cardiovascular signs requires a wearable and connected electrocardiogram (ECG) healthcare device. It increases user's comfort and diagnosis quality of chronic cardiac and/or high-risk patients. This paper covers the enormous data to be transmitted from the ECG device to the physician's, namely the cardiologist's, control unit. Existent ECG devices uniformly sample analog signals and convert them to digital samples which are compressed before data transmission. However, event-driven sampling simultaneously compresses and samples. Therefore, this paper quantitatively compares successive approximation register analog-to-digital converter (SAR ADC) with discrete wavelet transform (DWT) compression and level-crossing analog-to-digital converter (LC-ADC). Evaluation metrics are the percent root-mean-square difference ( ), bit compression ratio ( ) and data length in bits. When a 12-bit reconstruction is operated on the outputs of an 8-bit LC-ADC with 12-bit and 10-kHz reference counter, the is equal to 80% for 75% of test ECG signals. That is better than the 71.87% of the 12-bit 1-kHz SAR ADC with DWT compression. The modeled LC-ADC guarantees a signal quality in terms of comparable to the of the SAR ADC with DWT compression. The data length in bits of the LC-ADC is lower than the data length in bits of the SAR ADC with more than 14-bit resolution with DWT compression for 82% of the test ECG signals. However, for lower resolutions, to obtain lower power consumption for radiofrequency transmission, a better alternative remains the SAR ADC with DWT compression.
对心血管体征进行长期监测需要一种可穿戴且联网的心电图（ECG）医疗设备。它能提高用户的舒适度以及慢性心脏病和/或高危患者的诊断质量。本文涵盖了从ECG设备传输到医生（即心脏病专家）控制单元的大量数据。现有的ECG设备统一对模拟信号进行采样，并将其转换为数字样本，在数据传输前进行压缩。然而，事件驱动采样同时进行压缩和采样。因此，本文定量比较了逐次逼近寄存器模数转换器（SAR ADC）与离散小波变换（DWT）压缩以及过零模数转换器（LC - ADC）。评估指标为均方根差百分比（ ）、比特压缩率（ ）和比特数据长度。当对具有12位和10kHz参考计数器的8位LC - ADC的输出进行12位重建时，对于75%的测试ECG信号，均方根差百分比等于80%。这优于具有DWT压缩的12位1kHz SAR ADC的71.87%。所建模的LC - ADC在均方根差百分比方面保证了与具有DWT压缩的SAR ADC相当的信号质量。对于82%的测试ECG信号，LC - ADC的比特数据长度低于具有DWT压缩且分辨率超过14位的SAR ADC的比特数据长度。然而，对于较低分辨率，为了在射频传输中获得更低的功耗，更好的选择仍然是具有DWT压缩的SAR ADC。
