A multistandard WLAN fractional-N frequency synthesizer is implemented in 0.13-�m CMOS. The PLL i... more A multistandard WLAN fractional-N frequency synthesizer is implemented in 0.13-�m CMOS. The PLL is able to generate carrier frequency for 802.11a/b/g and Hiper- LAN2 standards. Given the wide tuning range required, the VCO adopts a switched tuning LC tank together with an Adaptive Frequency Calibration (AFC) technique. Measured integral phase noise is less than 3° rms and the 40-MHz ref- erence spurs are below -40 dBc. Lock time is less than 200� �� �sec. The power consumption is about 50 mW from a 1.2- V supply.
The paper describes a multi-channel neural spike recording system sensing and processing the acti... more The paper describes a multi-channel neural spike recording system sensing and processing the action potentials (APs) detected by an electrode array implanted in the cortex of freely-behaving small laboratory animals. The core of the system is a custom integrated circuit (IC), with low-noise analog front-end interfaced to a 16 electrode array followed by a single 8-bit SAR ADC, a digital
This paper reports a multi-channel neural spike recording system-on-chip (SoC) with digital data ... more This paper reports a multi-channel neural spike recording system-on-chip (SoC) with digital data compression and wireless telemetry. The circuit (16 active channels plus 48 ”mute” lines) demonstrates the potentials of a 64-channel system made by a low-noise analog front-end, a single 8-bit SAR ADC, followed by digital signal compression and transmission units. The 400-MHz transmitter uses a Manchester-Coded Frequency Shift
An increasing popularity of multichannel recordings from freely behaving animals and the need to ... more An increasing popularity of multichannel recordings from freely behaving animals and the need to develop a practical brain-machine interface has fuelled the development of miniature multichannel recording systems. Here we describe our prototype miniature 64-channel acquisition system that could be used for multichannel recordings in freely behaving monkeys or other large animals. The system's features include an high impedance input for neurophysiology electrodes, an integrated battery fed circuitry with a 64 low-noise multiplexed amplifiers array that permits the parallel recording of all channels, a 10-bit resolution ADC, an FPGA digital core for online processing and data transmission, a USB 2.0 link and a custom software for data visualization and whole system control.
ABSTRACT This paper describes a simulation method to compute oscillator phase noise which combine... more ABSTRACT This paper describes a simulation method to compute oscillator phase noise which combines transient and periodic-transfer-function analyses, available in most of the commercial circuit simulators. The proposed calculation technique is simple to implement and provides the designer a deep insight into phase noise generation mechanisms for both stationary and cyclostationary sources, thus resulting a powerful tool to perform an optimum design in RF applications.
ABSTRACT The adoption of differential tuning in oscillators provides cancellation of common-mode ... more ABSTRACT The adoption of differential tuning in oscillators provides cancellation of common-mode disturbances, and thus, it is expected to lower phase noise and power supply pulling. However, the direct application of differential tuning increases the capacitor nonlinearity, and in turn, it can raise the flicker-induced phase noise. This upconversion mechanism, based on non-linearities, is quantitatively assessed and a modified configuration circumventing this phenomenon is proposed and applied to the design of a 1.8-GHz LC oscillator in 0.35-μm CMOS technology. The simulated 1/f3, phase noise is reduced by 20 dB, without impairing the tuning range and supply pulling.
This work proposes two novel simulation techniques that allow for fast and accurate predictions o... more This work proposes two novel simulation techniques that allow for fast and accurate predictions of phase noise in oscillators even adopting inexpensive software, such as PSpice. The traditional harmonic tone insertion is initially discussed, by applying it to a LC-tuned oscillator taken as benchmark. Then a first, much faster technique based on sensitivity analysis is proposed, which is suitable for
This paper shows, for the first time, a complete magnetic field sensing system including a Lorent... more This paper shows, for the first time, a complete magnetic field sensing system including a Lorentz-force sensor operating out of resonance coupled to an integrated circuit for sensing and actuating the device. Working out of resonance, the trade-off between maximum sensing bandwidth and minimum detectable magnetic field is overwhelmed, improving the resolution and enlarging the bandwidth. However, the reduction of signal amplitude makes the readout electronics a critical block. Measurements carried-out on the whole system show an achievable resolution of 180 nT·mA/√Hz over a 150-Hz bandwidth and an overall power consumption of 460 μW. The integrated readout circuit low-noise performance does not limit the resolution, which is set by the MEMS thermomechanical noise.
For extracellular recordings from neurons, it is desirable to use the same electrode for stimulat... more For extracellular recordings from neurons, it is desirable to use the same electrode for stimulation as well as for recording. Since neural preamplifiers usually exhibit high-pass filtering at frequencies as low as 0.1 Hz, the recovery from saturation is typically very slow. Consequently, following stimulation, no signal can be detected for up to several seconds. This is unacceptably slow response of the preamplifier because the majority of neurons fires action potentials within first milliseconds following stimulation. Here we propose to use a switched-capacitor preamplifier with adjustable pass-band for fast recovery from saturation caused by stimulation via the recording electrode. The idea was tested in a real preamplifier manufactured with a standard CMOS technology (0.35 microm). In control conditions, the high-pass filter was set to 100 Hz and, during stimulation, was shifted to 10 kHz. Such a shift allows the reduction of the recovery time from tens of milliseconds to sub-millisecond range.
A multistandard WLAN fractional-N frequency synthesizer is implemented in 0.13-�m CMOS. The PLL i... more A multistandard WLAN fractional-N frequency synthesizer is implemented in 0.13-�m CMOS. The PLL is able to generate carrier frequency for 802.11a/b/g and Hiper- LAN2 standards. Given the wide tuning range required, the VCO adopts a switched tuning LC tank together with an Adaptive Frequency Calibration (AFC) technique. Measured integral phase noise is less than 3° rms and the 40-MHz ref- erence spurs are below -40 dBc. Lock time is less than 200� �� �sec. The power consumption is about 50 mW from a 1.2- V supply.
The paper describes a multi-channel neural spike recording system sensing and processing the acti... more The paper describes a multi-channel neural spike recording system sensing and processing the action potentials (APs) detected by an electrode array implanted in the cortex of freely-behaving small laboratory animals. The core of the system is a custom integrated circuit (IC), with low-noise analog front-end interfaced to a 16 electrode array followed by a single 8-bit SAR ADC, a digital
This paper reports a multi-channel neural spike recording system-on-chip (SoC) with digital data ... more This paper reports a multi-channel neural spike recording system-on-chip (SoC) with digital data compression and wireless telemetry. The circuit (16 active channels plus 48 ”mute” lines) demonstrates the potentials of a 64-channel system made by a low-noise analog front-end, a single 8-bit SAR ADC, followed by digital signal compression and transmission units. The 400-MHz transmitter uses a Manchester-Coded Frequency Shift
An increasing popularity of multichannel recordings from freely behaving animals and the need to ... more An increasing popularity of multichannel recordings from freely behaving animals and the need to develop a practical brain-machine interface has fuelled the development of miniature multichannel recording systems. Here we describe our prototype miniature 64-channel acquisition system that could be used for multichannel recordings in freely behaving monkeys or other large animals. The system's features include an high impedance input for neurophysiology electrodes, an integrated battery fed circuitry with a 64 low-noise multiplexed amplifiers array that permits the parallel recording of all channels, a 10-bit resolution ADC, an FPGA digital core for online processing and data transmission, a USB 2.0 link and a custom software for data visualization and whole system control.
ABSTRACT This paper describes a simulation method to compute oscillator phase noise which combine... more ABSTRACT This paper describes a simulation method to compute oscillator phase noise which combines transient and periodic-transfer-function analyses, available in most of the commercial circuit simulators. The proposed calculation technique is simple to implement and provides the designer a deep insight into phase noise generation mechanisms for both stationary and cyclostationary sources, thus resulting a powerful tool to perform an optimum design in RF applications.
ABSTRACT The adoption of differential tuning in oscillators provides cancellation of common-mode ... more ABSTRACT The adoption of differential tuning in oscillators provides cancellation of common-mode disturbances, and thus, it is expected to lower phase noise and power supply pulling. However, the direct application of differential tuning increases the capacitor nonlinearity, and in turn, it can raise the flicker-induced phase noise. This upconversion mechanism, based on non-linearities, is quantitatively assessed and a modified configuration circumventing this phenomenon is proposed and applied to the design of a 1.8-GHz LC oscillator in 0.35-μm CMOS technology. The simulated 1/f3, phase noise is reduced by 20 dB, without impairing the tuning range and supply pulling.
This work proposes two novel simulation techniques that allow for fast and accurate predictions o... more This work proposes two novel simulation techniques that allow for fast and accurate predictions of phase noise in oscillators even adopting inexpensive software, such as PSpice. The traditional harmonic tone insertion is initially discussed, by applying it to a LC-tuned oscillator taken as benchmark. Then a first, much faster technique based on sensitivity analysis is proposed, which is suitable for
This paper shows, for the first time, a complete magnetic field sensing system including a Lorent... more This paper shows, for the first time, a complete magnetic field sensing system including a Lorentz-force sensor operating out of resonance coupled to an integrated circuit for sensing and actuating the device. Working out of resonance, the trade-off between maximum sensing bandwidth and minimum detectable magnetic field is overwhelmed, improving the resolution and enlarging the bandwidth. However, the reduction of signal amplitude makes the readout electronics a critical block. Measurements carried-out on the whole system show an achievable resolution of 180 nT·mA/√Hz over a 150-Hz bandwidth and an overall power consumption of 460 μW. The integrated readout circuit low-noise performance does not limit the resolution, which is set by the MEMS thermomechanical noise.
For extracellular recordings from neurons, it is desirable to use the same electrode for stimulat... more For extracellular recordings from neurons, it is desirable to use the same electrode for stimulation as well as for recording. Since neural preamplifiers usually exhibit high-pass filtering at frequencies as low as 0.1 Hz, the recovery from saturation is typically very slow. Consequently, following stimulation, no signal can be detected for up to several seconds. This is unacceptably slow response of the preamplifier because the majority of neurons fires action potentials within first milliseconds following stimulation. Here we propose to use a switched-capacitor preamplifier with adjustable pass-band for fast recovery from saturation caused by stimulation via the recording electrode. The idea was tested in a real preamplifier manufactured with a standard CMOS technology (0.35 microm). In control conditions, the high-pass filter was set to 100 Hz and, during stimulation, was shifted to 10 kHz. Such a shift allows the reduction of the recovery time from tens of milliseconds to sub-millisecond range.
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Papers by Andrea Bonfanti