{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,23]],"date-time":"2026-08-23T16:00:17Z","timestamp":1787500817135,"version":"build-2736575974"},"reference-count":50,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2018,1,11]],"date-time":"2018-01-11T00:00:00Z","timestamp":1515628800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"MEXT Grants-in-Aid for Scientific Research","award":["15H05525"],"award-info":[{"award-number":["15H05525"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A time-domain analog spatial compressed sensing encoder for neural recording applications is proposed. Owing to the advantage of MEMS technologies, the number of channels on a silicon neural probe array has doubled in 7.4 years, and therefore, a greater number of recording channels and higher density of front-end circuitry is required. Since neural signals such as action potential (AP) have wider signal bandwidth than that of an image sensor, a data compression technique is essentially required for arrayed neural recording systems. In this paper, compressed sensing (CS) is employed for data reduction, and a novel time-domain analog CS encoder is proposed. A simpler and lower power circuit than conventional analog or digital CS encoders can be realized by using the proposed CS encoder. A prototype of the proposed encoder was fabricated in a 180 nm 1P6M CMOS process, and it achieved an active area of 0.0342 mm 2 \/ ch . and an energy efficiency of 25.0 pJ \/ ch . \u00b7 conv .<\/jats:p>","DOI":"10.3390\/s18010184","type":"journal-article","created":{"date-parts":[[2018,1,11]],"date-time":"2018-01-11T13:36:15Z","timestamp":1515677775000},"page":"184","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["A Time-Domain Analog Spatial Compressed Sensing Encoder for Multi-Channel Neural Recording"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5739-7115","authenticated-orcid":false,"given":"Takayuki","family":"Okazawa","sequence":"first","affiliation":[{"name":"Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1451-9287","authenticated-orcid":false,"given":"Ippei","family":"Akita","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,1,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"6704","DOI":"10.3390\/s8106704","article-title":"NeuroMEMS: Neural probe microtechnologies","volume":"8","author":"HajjHassan","year":"2008","journal-title":"Sensors"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"238","DOI":"10.1109\/TBME.1970.4502738","article-title":"An integrated-circuit approach to extracellular microelectrodes","volume":"BME-17","author":"Wise","year":"1970","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"414","DOI":"10.1088\/0960-1317\/12\/4\/312","article-title":"A 32-site neural recording probe fabricated by DRIE of SOI substrates","volume":"12","author":"Norlin","year":"2002","journal-title":"J. Micromech. Microeng."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1016\/j.snb.2003.10.009","article-title":"A neural probe process enabling variable electrode configurations","volume":"102","author":"Kindlundh","year":"2004","journal-title":"Sens. Actuators B Chem."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1109\/JSSC.2006.886567","article-title":"A low-power integrated circuit for a wireless 100-electrode neural recording system","volume":"42","author":"Harrison","year":"2007","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"322","DOI":"10.1109\/TNSRE.2009.2023298","article-title":"Wireless neural recording with single low-power integrated circuit","volume":"17","author":"Harrison","year":"2009","journal-title":"IEEE Trans. Neural Syst. Rehab. Eng."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1109\/TBCAS.2010.2041350","article-title":"The 128-channel fully differential digital integrated neural recording and stimulation interface","volume":"4","author":"Shahrokhi","year":"2010","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1109\/TBCAS.2013.2255874","article-title":"A 100-channel hermetically sealed implantable device for chronic wireless neurosensing applications","volume":"7","author":"Yin","year":"2013","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"670","DOI":"10.1038\/nmeth.2936","article-title":"Chronic, wireless recordings of large scale brain activity in freely moving rhesus monkeys","volume":"11","author":"Schwarz","year":"2014","journal-title":"Nat. Methods"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Johnson, B.C., Gambini, S., Izyumin, I., Moin, A., Zhou, A., Alexandrov, G., Santacruz, S.R., Rabaey, J.M., Carmena, J.M., and Muller, R. (2017, January 5\u20138). An implantable 700 \u03bcW 64-channel neuromodulation IC for simultaneous recording and stimulation with rapid artifact recovery. Proceedings of the 2017 Symposium on VLSI Circuits, Kyoto, Japan.","DOI":"10.23919\/VLSIC.2017.8008543"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1075","DOI":"10.1109\/TBME.2007.894986","article-title":"A fully integrated mixed-signal neural processor for implantable multichannel cortical recording","volume":"54","author":"Sodagar","year":"2007","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2591","DOI":"10.1109\/JSSC.2009.2023159","article-title":"An implantable 64-channel wireless microsystem for single-unit neural recording","volume":"44","author":"Sodagar","year":"2009","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"360","DOI":"10.1109\/TBCAS.2010.2078814","article-title":"An inductively powered scalable 32-channel wireless neural recording system-on-a-chip for neuroscience applications","volume":"4","author":"Lee","year":"2010","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Du, J., Blanche, T.J., Harrison, R.R., Lester, H.A., and Masmanidis, S.C. (2011). Multiplexed, high density electrophysiology with nanofabricated neural probes. PLoS ONE, 6.","DOI":"10.1371\/journal.pone.0026204"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"601","DOI":"10.1109\/TBCAS.2013.2281772","article-title":"Massively-parallel neuromonitoring and neurostimulation rodent headset with nanotextured flexible microelectrodes","volume":"7","author":"Bagheri","year":"2013","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"248","DOI":"10.1109\/JSSC.2013.2284347","article-title":"An implantable 455-active-electrode 52-channel CMOS neural probe","volume":"49","author":"Lopez","year":"2014","journal-title":"IEEE J. Solid State Circuits"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1226","DOI":"10.1016\/j.mejo.2014.01.018","article-title":"Multichannel neural recording system based on family ASICs processed in submicron technology","volume":"45","author":"Zoladz","year":"2014","journal-title":"Microelectronics J."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Park, S.Y., Cho, J., and Yoon, E. (2017, January 5\u20138). 3.37 \u03bcW\/Ch Modular Scalable Neural Recording System with Embedded Lossless Compression for Dynamic Power Reduction. Proceedings of the 2017 Symposium on VLSI Circuits, Kyoto, Japan.","DOI":"10.23919\/VLSIC.2017.8008468"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"735","DOI":"10.1109\/TBCAS.2014.2298860","article-title":"A 0.45 V 100-channel neural-recording IC with sub-\u03bcW\/channel consumption in 0.18 CMOS","volume":"7","author":"Han","year":"2013","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1109\/JSSC.2009.2035196","article-title":"Switch-matrix-based high-density microelectrode array in CMOS technology","volume":"45","author":"Frey","year":"2010","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2191","DOI":"10.1016\/j.bios.2008.11.028","article-title":"Microelectronic system for high-resolution mapping of extracellular electric fields applied to brain slices","volume":"24","author":"Frey","year":"2009","journal-title":"Biosens. Bioelectron."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"312","DOI":"10.1109\/TNSRE.2009.2021607","article-title":"A 128-channel 6 mW wireless neural recording IC with spike feature extraction and UWB transmitter","volume":"17","author":"Chae","year":"2009","journal-title":"IEEE Trans. Neural Syst. Rehab. Eng."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1068","DOI":"10.1109\/TBCAS.2016.2514522","article-title":"Wireless multichannel neural necording with a 128-Mbps UWB transmitter for an implantable brain-machine interfaces","volume":"10","author":"Ando","year":"2016","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1038\/nn.2731","article-title":"How advances in neural recording affect data analysis","volume":"14","author":"Stevenson","year":"2011","journal-title":"Nat. Neurosci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"4572","DOI":"10.3390\/s110504572","article-title":"Recent advances in neural recording microsystems","volume":"11","author":"Gosselin","year":"2011","journal-title":"Sensors"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1289","DOI":"10.1109\/TIT.2006.871582","article-title":"Compressed sensing","volume":"52","author":"Donoho","year":"2006","journal-title":"IEEE Trans. Info. Theory"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"5406","DOI":"10.1109\/TIT.2006.885507","article-title":"Near-optimal signal recovery from random projections: Universal encoding strategies?","volume":"52","author":"Candes","year":"2006","journal-title":"IEEE Trans. Inf. Theory"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"744","DOI":"10.1109\/JSSC.2011.2179451","article-title":"Design and analysis of a hardware-efficient compressed sensing architecture for data compression in wireless sensors","volume":"47","author":"Chen","year":"2012","journal-title":"IEEE J. Solid State Circ."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Sun, C., Li, W., and Chen, W. (2017). A compressed sensing based method for reducing the sampling time of a high resolution pressure sensor array system. Sensors, 17.","DOI":"10.3390\/s17081848"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Tseng, Y., and Chen, Y. (2017). Adaptive integration of the compressed algorithm of CS and NPC for the ECG signal compressed algorithm in VLSI implementation. Sensors, 17.","DOI":"10.3390\/s17102288"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Liu, X., Zhu, H., Zhang, M., Richardson, A.G., Lucas, T.H., and Spiegel, J.V. (2015, January 24\u201327). Design of a low-noise, high power efficiency neural recording front-end with an integrated real-time compressed sensing unit. Proceedings of the 2015 IEEE International Symposium on Circuits and Systems (ISCAS), Lisbon, Portugal.","DOI":"10.1109\/ISCAS.2015.7169317"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"874","DOI":"10.1109\/TBCAS.2016.2574362","article-title":"A fully integrated wireless compressed sensing neural signal acquisition system for chronic recording and brain machine interface","volume":"10","author":"Liu","year":"2016","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"857","DOI":"10.1109\/TBCAS.2014.2304582","article-title":"Compact low-power cortical recording architecture for compressive multichannel data acquisition","volume":"8","author":"Shoaran","year":"2014","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Shoaran, M., Lopez, M.M., Pasupureddi, V.S.R., Leblebici, Y., and Schmid, A. (2013, January 19\u201323). A low-power area-efficient compressive sensing approach for multi-channel neural recording. Proceedings of the 2013 IEEE International Symposium on Circuits and Systems, Beijing, China.","DOI":"10.1109\/ISCAS.2013.6572310"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"318","DOI":"10.1109\/JSSC.2012.2214851","article-title":"CMOS image sensor with per-column \u03a3\u0394 ADC and programmable compressed sensing","volume":"48","author":"Oike","year":"2013","journal-title":"IEEE J. Solid State Circuits"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"19880","DOI":"10.3390\/s150819880","article-title":"Efficient sparse signal transmission over a lossy link using compressive sensing","volume":"15","author":"Wu","year":"2015","journal-title":"Sensors"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"24305","DOI":"10.3390\/s141224305","article-title":"Effective low-power wearable wireless surface EMG sensor design based on analog-compressed sensing","volume":"14","author":"Balouchestani","year":"2014","journal-title":"Sensors"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1109\/TCSII.2013.2296133","article-title":"new improved algorithms for compressive sensing based on lp Norm","volume":"61","author":"Pant","year":"2014","journal-title":"IEEE Trans. Circuits Syst."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2009","DOI":"10.1109\/TSP.2013.2241055","article-title":"Extension of SBL algorithms for the recovery of block sparse signals with intra-block correlation","volume":"61","author":"Zhang","year":"2013","journal-title":"IEEE Trans. Signal Proc."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"541","DOI":"10.1109\/TCSI.2008.2002547","article-title":"Noise analysis for comparator-based circuits","volume":"56","author":"Sepke","year":"2009","journal-title":"IEEE Trans. Circuits Syst. I"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"790","DOI":"10.1109\/4.766813","article-title":"Jitter and phase noise in ring oscillators","volume":"34","author":"Hajimiri","year":"1999","journal-title":"IEEE J. Solid State Circuits"},{"key":"ref_42","unstructured":"Grant, M.C., and Boyd, S.P. (2017, October 11). CVX: Matlab Software for Disciplined Convex Programming. Available online: http:\/\/cvxr.com\/cvx\/."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1002\/cta.1955","article-title":"A 128-channel discrete cosine transform-based neural signal processor for implantable neural recording microsystems","volume":"43","author":"Jannesari","year":"2015","journal-title":"Int. J. Circuit Theory Appl."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"R53","DOI":"10.1088\/0954-898X_9_4_001","article-title":"A review of methods for spike sorting: The detection and classification of neural action potentials","volume":"9","author":"Lewicki","year":"1998","journal-title":"Netw. Comput. Neural Syst."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"420","DOI":"10.1109\/TBCAS.2016.2618319","article-title":"System-level design of a 64-channel low power neural spike recording sensor","volume":"11","author":"Darie","year":"2017","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"4311","DOI":"10.1109\/TSP.2006.881199","article-title":"K-SVD: An algorithm for designing overcomplete dictionaries for sparse representation","volume":"54","author":"Aharon","year":"2006","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"1201","DOI":"10.1109\/TCSI.2017.2649572","article-title":"Rakeness-Based Design of Low-Complexity Compressed Sensing","volume":"64","author":"Mangia","year":"2017","journal-title":"IEEE Trans. Circuits Syst. I"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1569","DOI":"10.1109\/TNN.2003.820440","article-title":"Simple model of spiking neurons","volume":"14","author":"Izhikevich","year":"2003","journal-title":"IEEE Trans. Neural Netw."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/S0092-8240(05)80004-7","article-title":"A quantitative description of membrane current and its application to conduction and excitation in nerve","volume":"52","author":"Hodgkin","year":"1990","journal-title":"Bull. Math. Biol."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Nunez, P.L., and Srinivasan, R. (2006). Electric Fields of the Brain: The neurophysics of EEG, Oxford University Press. [2nd ed.].","DOI":"10.1093\/acprof:oso\/9780195050387.001.0001"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/1\/184\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T14:50:53Z","timestamp":1760194253000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/1\/184"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,1,11]]},"references-count":50,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2018,1]]}},"alternative-id":["s18010184"],"URL":"https:\/\/doi.org\/10.3390\/s18010184","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,1,11]]}}}