Common-mode Rejection Techniques Research Articles

Noise Suppression of Nitrogen-Vacancy Magnetometer in Lock-In Detection Method by Using Common Mode Rejection.

Nitrogen-vacancy (NV) centers in diamonds are promising solid-state magnetic sensors with potential applications in power systems, geomagnetic navigation, and diamond NV color center current transformers, in which both high bandwidth and high magnetic field resolution are required. The wide bandwidth requirement often necessitates high laser power, but this induces significant laser fluctuation noise that affects the detection magnetic field resolution severely. Therefore, enhancement of the magnetic field resolution of wide-bandwidth NV center magnetic sensors is highly important because of the reciprocal effects of the bandwidth and magnetic field resolution. In this article, we develop a common mode rejection (CMR) model to eliminate the laser noise effectively. The simulation results show that the noise level of the light-detected magnetic resonance signal is significantly reduced by a factor of 6.2 after applying the CMR technique. After optimization of the laser power and modulation frequency parameters, the optimal system bandwidth was found to be 75 Hz. Simultaneously, the system's detection magnetic field resolution was enhanced significantly, increasing from 4.49 nT/Hz1/2 to 790.8 pT/Hz1/2, which represents an improvement of nearly 5.7 times. This wide-bandwidth, high-magnetic field resolution NV color center magnetic sensor will have applications including power systems, geomagnetic navigation, and diamond NV color center current transformers.

A Noise-Efficient 36 nV/ $\surd $ Hz Chopper Amplifier Using an Inverter-Based 0.2-V Supply Input Stage

This paper presents an analog front end (AFE) that achieves a high noise efficiency by using a chopper amplifier with a 0.2-V supply inverter-based input stage followed by a 0.8-V supply stage. The high input-stage current needed to reduce the input-referred noise is drawn from the 0.2-V supply, significantly reducing power consumption. The 0.8 V stage provides high gain and signal swing, improving linearity. Biasing and common-mode rejection techniques for the ultra-low-voltage stage are presented. The AFE is implemented in a 0.18 $\mu \text{m}$ CMOS process and integrates the chopper low-noise instrumentation amplifier, a programmable-gain amplifier, and an antialiasing filter. The AFE consumes 0.79 $\mu \text{W}$ and achieves a competitive power efficiency factor (PEF) of 1.6 and an input noise of 0.94 $\mu \text{V}_{\text {rms}}$ integrated from 0.5 to 670 Hz while maintaining a 36 nV/ $\surd $ Hz input noise density down to 0.5 Hz. The included 0.8/0.2-V buck converter may be used to provide the 0.2-V supply at 72%–74% efficiency without significantly increasing noise, yielding a PEF of 1.8.

Ultra Fast Response AC-Coupled Burst-Mode Receiver with High Sensitivity and Wide Dynamic Range for 10G-EPON System

A 10-Gbit/s-class ac-coupled average-detection-type burst-mode receiver (B-Rx) with an ultra fast response and a high tolerance to the long consecutive identical digits has been developed. Key features of the circuit design are the baseline-wander common-mode rejection technique and the inverted distortion technique adopted in the limiting amplifier to cope with both the fast response and the high tolerance. Our B-Rx with newly developed limiting amplifier IC achieved a settling time of less than 150ns, a sensitivity of -29.8dBm, and a dynamic range of 23.8dB with a 231-1 pseudo random bit sequences. Moreover, we also describe several potential B-Rx applications. We achieved better performance by applying the proposed systems to our B-Rx.

A resonant half bridge driver with novel common mode rejection technique implemented in 1.0 μm high voltage (650 V) DIMOS process

In this paper, a half bridge convert driver IC with novel common mode rejection technique is designed and implemented in 1.0μm high voltage (650V) Dielectric Isolation MOS (DIMOS) process. The Designed IC is suitable for medium power (under 500W) applications such as consumer electronics. Half bridge converter driver IC with a novel common mode rejection technique, which is composed of noise filter and set inhibitor, shows high dv/dt noise immunity up to 66.67V/ns. Spectre simulation was performed to verify the electrical characteristics of the designed IC.

Frequency-tunable pre-stabilized lasers for LISA via sideband locking

Laser frequency noise mitigation is one of the most challenging aspects of the LISA interferometric measurement system. The unstabilized frequency fluctuations must be suppressed by roughly 12 orders of magnitude in order to achieve stability sufficient for gravitational wave detection. This enormous suppression will be achieved through a combination of stabilization and common-mode rejection techniques. The stabilization component will itself be achieved in two stages: pre-stabilization to a local optical reference followed by arm locking to some combination of the inter-spacecraft distances. In order for these two stabilization stages to work simultaneously, the lock-point of the pre-stabilization loop must be frequency tunable. The current baseline stabilization technique, Pound–Drever–Hall locking to an optical cavity, does not provide tunability between cavity resonances. Here we present a modification to the baseline technique that allows the laser to be locked to a cavity resonance with an adjustable frequency offset. This technique requires no modifications to the optical cavity itself, thus preserving the stability of the frequency reference. We present measurements of the system performance and demonstrate that the offset locking techniques are compatible with arm locking.

A digital common-mode rejection technique for differential analog-to-digital conversion

A multibit /spl Delta//spl Sigma/ analog-to-digital converter can achieve high resolution with a lower order /spl Delta//spl Sigma/ modulator and lower oversampling ratio than a single-bit design, but it requires a multibit internal flash analog-to-digital converter rather than a simple comparator. In an implementation with a fully differential analog front end, the flash analog-to-digital converter must quantize a differential voltage relative to a set of differential reference voltages. Though analog techniques for differential analog-to-digital conversion exist, implementing them in a low-voltage single-poly CMOS process is a challenging circuit design problem. This paper presents a digital common-mode rejection technique for differential analog-to-digital conversion (ADC), which avoids the circuit complexity and die area requirements of analog common-mode rejection techniques. This technique was used to implement the internal quantizer in two high-performance single-poly CMOS ADC /spl Delta//spl Sigma/ modulator prototypes with over 98-dB peak signal-to-noise-and-distortion ratio and 105-dB spurious-free dynamic range. Implementation details, die area requirements, and measured common-mode rejection are presented for the prototype. Signal-processing details of digital common-mode rejection within the /spl Delta//spl Sigma/ modulator are presented, showing that injected common-mode noise results only in modulation of the quantization error power and does not create spurious tones.

In-process sensor for surface profile measurement applying a common-mode rejection technique

An optical non-contact profilometer is presented for super-smooth surfaces, which applies a so-called common-mode rejection technique. Environmental disturbances and laser amplitude noise, which commonly exist in similar instruments, are overcome in this system. The overall simplicity of the optics and electronics, the low cost of the components and the ease of alignment make this a convenient system to implement.

Instrumental noise effect in an optical heterodyne profiler

An optical heterodyne profiler has been developed for measuring surface roughness at Brookhaven National Laboratory. The height measurement sensitivity and lateral resolution are 1.1 Å and 4 µm, respectively, when a 40× objective is used. A Zeeman-split He-Ne laser is the light source. A noncontact measurement system is designed as an optical common-path interferometer. Optical and electronic common-mode rejection techniques are employed to minimize the effects of environmental conditions. The effect of the system noise is analyzed in detail. The effect of varying the number of samples at each sampling point is shown. The comparisons of the system noises with different objectives, 5×, 10×, 20×, and 40×, are presented.

Optical Heterodyne Profilometer

An optical heterodyne profilometer breadboard with surface roughness measurement sensitivity to 0.1 A has been developed and demonstrated. Optical and electronic common-mode rejection techniques were employed in the optical heterodyne precision phase measurement scheme to resolve the optical phase to one part in thirty thousand. Vibration-induced optical phase jitter in the system was nearly eliminated by these common-mode rejection techniques. This noncontact profilometer is capable of characterizing mirror surfaces and is not limited only to flat and/or highly reflective surfaces. Con-cave surfaces, such as the x-ray mirrors for the Advanced X-ray Astrophysical Facility (AXAF), may be characterized as well. Several mirror samples, including two x-ray mirror samples, have been characterized with the optical heterodyne profilometer. Roughness measurement results for the x-ray mirror samples have been compared with those obtained by other methods.

Common mode rejection techniques in conjugate eye movement recording during sleep.

ABSTRACTCommon mode rejection is viewed as a general technique that can be used in certain biological recording situations to increase the signal to noise ratio, in which the noise component is of biological rather than electrical origin. The recording of conjugate eye movements during sleep is cited as an example.