1-3hit |
Ming NI Yan HAN Ray C. C. CHEUNG Xuemeng ZHOU
This paper presents a hippocampal cognitive prosthesis chip designed for restoring the ability to form new long-term memories due to hippocampal system damage. The system-on-chip (SOC) consists of a 16-channel micro-power low-noise amplifier (LNA), high-pass filters, analog-digital converters (ADCs), a 16-channel spike-sorter, a generalized Laguerre-Volterra model multi-input, multi-output (GLVM-MIMO) hippocampal processor, an 8-channel neural stimulator and peripheral circuits. The proposed LNA achieved a voltage gain of 50dB, input-referred noise of 3.95µVrms, and noise efficiency factor (NEF) of 3.45 with the power consumption of 3.3µW. High-pass filters with a 300-Hz bandwidth are used to filter out the unwanted local field potential (LFP). 4 12-bit successive approximation register (SAR) ADCs with a signal-to-noise-and-distortion ratio (SNDR) of 63.37dB are designed for the digitization of the neural signals. A 16-channel spike-sorter has been integrated in the chip enabling a detection accuracy of 98.3% and a classification accuracy of 93.4% with power consumption of 19µW/ch. The MIMO hippocampal model processor predict output spatio-temporal patterns in CA1 according to the recorded input spatio-temporal patterns in CA3. The neural stimulator performs bipolar, symmetrical charge-balanced stimulation with a maximum current of 310µA, triggered by the processor output. The chip has been fabricated in 40nm standard CMOS technology, occupying a silicon area of 3mm2.
Jason CHOU Yan HAN Bahram JALALI
The system uses spectral shaping of a supercontinuum source followed by wavelength-to-time mapping to generate ultra wideband RF waveforms with arbitrary modulation. It employs an adaptive computer control to mitigate the non-ideal features inherent in the optical source and in the spectrum modulation process. As proof of concept, ultra-wideband frequency hopped CDMA waveforms are demonstrated.
Yan HAN Bahram JALALI Jeehoon HAN Byoungjoon SEO Harold FETTERMAN
We report on the first demonstration of single sideband (SSB) modulated time stretch system. In addition, we present an analytical model relating the system performance to the phase and amplitude mismatches in the SSB modulator. The results show that, fortuitously, the system is tolerant to such mismatches. In particular, using commercially available components,the dispersion induced power penalty can be kept below 2.5 dB over 4-20 GHz bandwidth for any stretch factor. The experiments demonstrate 120 Gsample/s real-time capture of a 20 GHz SSB-modulated microwave signal.