An efficient design of 45-nm CMOS low-noise charge sensitive amplifier for wireless receivers

<p>Amplifiers are widely used in signal receiving circuits, such as antennas, medical imaging, wireless devices and many other applications. However, one of the most challenging problems when building an amplifier circuit is the noise, since it affects the quality of the intended received signal in most wireless applications. Therefore, a preamplifier is usually placed close to the main sensor to reduce the effects of interferences and to amplify the received signal without degrading the signal-to-noise ratio. Although different designs have been optimized and tested in the literature, all of them are using larger than 100 nm technologies which have led to a modest performance in terms of equivalent noise charge (ENC), gain, power consumption, and response time. In contrast, we consider in this paper a new amplifier design technology trend and move towards sub 100 nm to enhance its performance. In this work, we use a pre-well-known design of a preamplifier circuit and rebuild it using 45 nm CMOS technology, which is made for the first time in such circuits. Performance evaluation shows that our proposed scaling technology, compared with other scaling technology, extremely reduces ENC of the circuit by more than 95%. The noise spectral density and time resolution are also reduced by 25% and 95% respectively. In addition, power consumption is decreased due to the reduced channel length by 90%. As a result, all of those enhancements make our proposed circuit more suitable for medical and wireless devices.</p>

Consequences of quantum noise control for the relaxation resonance frequency and phase noise in heterogeneous Silicon/III–V lasers

We have recently introduced a new semiconductor laser design which is based on an extreme, 99%, reduction of the laser mode absorption losses. In previous reports, we showed that this was achieved by a laser mode design which confines the great majority of the modal energy (> 99%) in a low-loss Silicon guiding layer rather than in highly-doped, thus lossy, III–V p$${}^+$$ + and n$${}^+$$ + layers, which is the case with traditional III–V lasers. The resulting reduced electron-field interaction was shown to lead to a commensurate reduction of the spontaneous emission rate by the excited conduction band electrons into the laser mode and thus to a reduction of the frequency noise spectral density of the laser field often characterized by the Schawlow–Townes linewidth. In this paper, we demonstrate theoretically and present experimental evidence of yet another major beneficial consequence of the new laser design: a near total elimination of the contribution of amplitude-phase coupling (the Henry $$\alpha $$ α parameter) to the frequency noise at “high” frequencies. This is due to an order of magnitude lowering of the relaxation resonance frequency of the laser. Here, we show that the practical elimination of this coupling enables yet another order of magnitude reduction of the frequency noise at high frequencies, resulting in a quantum-limited frequency noise spectral density of 130 Hz$$^2$$ 2 /Hz (linewidth of 0.4 kHz) for frequencies beyond the relaxation resonance frequency 680 MHz. This development is of key importance in the development of semiconductor lasers with higher coherence, particularly in the context of integrated photonics with a small laser footprint without requiring any sort of external cavity.

Investigation of random telegraph noise characteristics of Hf-based MONOS nonvolatile memory devices with HfO2 and HfON tunneling layer

This paper investigated the low frequency noise (LFN) utilizing 1/f noise and random telegraph noise (RTN) characteristics of Hf-based metal/oxide/nitride/oxide/silicon (MONOS) nonvolatile memory (NVM) device with HfO2 and HfON tunneling layer (TL). The low frequency noise spectral density (SID ) was investigated to evaluate the interface characteristics with fresh and after programming/erasing (P/E) cycles of 104. Both devices show similar slope of ~1/f in all of the frequency regions. Although HfON TL shows high SID compared to HfO2 TL, increased ratio is 15.4 which is low compared to HfO2 TL of 21.3. As decreasing the channel length from 10 to 2 μm, HfON TL shows small increased ratio of SID . Due to the nitrided characteristics, HfON TL suppress the degradation of interface. Finally, it is found that trap site of HfO2 TL is located near the interface by RTN measurement with capture (τC) and emission time constant (τE).

High Impedance Amplifiers for Non-Contact Bio-Potential Sensing

<p>This research develops a non-contact bio-potential sensor which can quickly respond to input transient events, is insensitive to mechanical disturbances, and operates with a bandwidth from 0.04Hz – 20kHz, with input voltage noise spectral density of 200nV / √Hz at 1kHz. Initial investigations focused on the development of an active biasing scheme to control the sensors input impedance in response to input transient events. This scheme was found to significantly reduce the settling time of the sensor; however the input impedance was degraded, and the device was sensitive to distance fluctuations. Further research was undertaken, and a circuit developed to preserve fast settling times, whilst decreasing the sensitivity to distance fluctuations. A novel amplifier biasing network was developed using a pair of junction field effect transistors (JFETs), which actively compensates for DC and low frequency interference, whilst maintaining high impedance at signal frequencies. This biasing network significantly reduces the settling time, allowing bio-potentials to be measured quickly after sensor application, and speeding up recovery when the sensor is in saturation. Further work focused on reducing the sensitivity to mechanical disturbances even further. A positive feedback path with low phase error was introduced to reduce the effective input capacitance of the sensor. Tuning of the positive feedback loop gain was achieved with coarse and fine control potentiometers, allowing very precise gains to be achieved. The sensor was found to be insensitive to distance fluctuations of up to 0.5mm at 1Hz, and up to 2mm at 5kHz. As a complement to the non-contact sensor, an amplifier to measure differential bio-potentials was developed. This differential amplifier achieved a CMRR of greater than 100dB up to 10kHz. Precise fixed gains of 20±0:02dB, 40±0:01dB, 60±0:03dB, and 80±0:3dB were achieved, with input voltage noise density of 15nV / √Hz at 1kHz.</p>

High Impedance Amplifiers for Non-Contact Bio-Potential Sensing

<p>This research develops a non-contact bio-potential sensor which can quickly respond to input transient events, is insensitive to mechanical disturbances, and operates with a bandwidth from 0.04Hz – 20kHz, with input voltage noise spectral density of 200nV / √Hz at 1kHz. Initial investigations focused on the development of an active biasing scheme to control the sensors input impedance in response to input transient events. This scheme was found to significantly reduce the settling time of the sensor; however the input impedance was degraded, and the device was sensitive to distance fluctuations. Further research was undertaken, and a circuit developed to preserve fast settling times, whilst decreasing the sensitivity to distance fluctuations. A novel amplifier biasing network was developed using a pair of junction field effect transistors (JFETs), which actively compensates for DC and low frequency interference, whilst maintaining high impedance at signal frequencies. This biasing network significantly reduces the settling time, allowing bio-potentials to be measured quickly after sensor application, and speeding up recovery when the sensor is in saturation. Further work focused on reducing the sensitivity to mechanical disturbances even further. A positive feedback path with low phase error was introduced to reduce the effective input capacitance of the sensor. Tuning of the positive feedback loop gain was achieved with coarse and fine control potentiometers, allowing very precise gains to be achieved. The sensor was found to be insensitive to distance fluctuations of up to 0.5mm at 1Hz, and up to 2mm at 5kHz. As a complement to the non-contact sensor, an amplifier to measure differential bio-potentials was developed. This differential amplifier achieved a CMRR of greater than 100dB up to 10kHz. Precise fixed gains of 20±0:02dB, 40±0:01dB, 60±0:03dB, and 80±0:3dB were achieved, with input voltage noise density of 15nV / √Hz at 1kHz.</p>

Tensional processes and perception of form in three selected compositions by Kaija Saariaho

<p>The primary feature that gives ‘spectral music’ its stylistic uniqueness within the field of art music is the blurring of the traditionally distinct roles of harmony and timbre, through the use of chords derived from the naturally occurring overtones of instrumental timbre (often referred to as timbre chords). Development of these chords typically occurs very gradually, meaning it is often difficult to perceive the overall form of a spectral work based on the progression through its constituent timbre chords. This approach contrasts with the traditional reliance in both art music and other Western music styles on perceivable pitch-based development as a primary means of providing musical tension and form. Composers of spectral music must rely on the manipulation and development of other musical parameters to provide sufficient interest through ‘foreground ornamentation’ while its underlying harmonic/timbral macrostructure unfolds beneath. This analysis shows how key musical parameters are manipulated over time to provide tension and resolution (or, in Wallace Berry’s terminology, ‘progressive and recessive processes’ ¹ ), giving spectral works a perceivable, dynamic form. Parameters examined include rate of harmonic change, dynamics, spectral/registral spread, rhythmic activity, sound/noise, spectral density and harmonicity/inharmonicity (the latter two providing a spectral analogue to conventional notions of dissonance). Particular focus is placed on the rate of harmonic change in the selected works and changes in the harmonicity/inharmonicity (through spectral distortion) of harmonic material that give spectral music its distinctive harmonic character. The way in which these ‘parameter curves’ intersect with one another is also examined. For this study, three works by Finnish composer Kaija Saariaho are analysed. The works cover a range of forces and display varying degrees of overtly ‘spectral’ influence: Nymphéa (1987) for string quartet and electronics, Du Cristal (1990) for orchestra, and Cendres (1998) for piano, cello and flute. Analysis of the background levels of parametric change reveal how Saariaho manages to maintain microstructural interest in her spectral works while adhering to an underlying macrostructural plan. Findings from this analysis will also be discussed in relation to how they have influenced my own creative output for my MMA portfolio.</p>

Tensional processes and perception of form in three selected compositions by Kaija Saariaho

<p>The primary feature that gives ‘spectral music’ its stylistic uniqueness within the field of art music is the blurring of the traditionally distinct roles of harmony and timbre, through the use of chords derived from the naturally occurring overtones of instrumental timbre (often referred to as timbre chords). Development of these chords typically occurs very gradually, meaning it is often difficult to perceive the overall form of a spectral work based on the progression through its constituent timbre chords. This approach contrasts with the traditional reliance in both art music and other Western music styles on perceivable pitch-based development as a primary means of providing musical tension and form. Composers of spectral music must rely on the manipulation and development of other musical parameters to provide sufficient interest through ‘foreground ornamentation’ while its underlying harmonic/timbral macrostructure unfolds beneath. This analysis shows how key musical parameters are manipulated over time to provide tension and resolution (or, in Wallace Berry’s terminology, ‘progressive and recessive processes’ ¹ ), giving spectral works a perceivable, dynamic form. Parameters examined include rate of harmonic change, dynamics, spectral/registral spread, rhythmic activity, sound/noise, spectral density and harmonicity/inharmonicity (the latter two providing a spectral analogue to conventional notions of dissonance). Particular focus is placed on the rate of harmonic change in the selected works and changes in the harmonicity/inharmonicity (through spectral distortion) of harmonic material that give spectral music its distinctive harmonic character. The way in which these ‘parameter curves’ intersect with one another is also examined. For this study, three works by Finnish composer Kaija Saariaho are analysed. The works cover a range of forces and display varying degrees of overtly ‘spectral’ influence: Nymphéa (1987) for string quartet and electronics, Du Cristal (1990) for orchestra, and Cendres (1998) for piano, cello and flute. Analysis of the background levels of parametric change reveal how Saariaho manages to maintain microstructural interest in her spectral works while adhering to an underlying macrostructural plan. Findings from this analysis will also be discussed in relation to how they have influenced my own creative output for my MMA portfolio.</p>

Quantum noise and vacuum fluctuations in balanced homodyne detections through ideal multi-mode detectors

The balanced homodyne detection as a readout scheme of gravitational-wave detectors is carefully examined from the quantum field theoretical point of view. The readout scheme in gravitational-wave detectors specifies the directly measured quantum operator in the detection. This specification is necessary when we apply the recently developed quantum measurement theory to gravitational-wave detections. We examine the two models of measurement. One is the model in which the directly measured quantum operator at the photodetector is Glauber’s photon number operator, and the other is the model in which the power operator of the optical field is directly measured. These two are regarded as ideal models of photodetectors. We first show these two models yield the same expectation value of the measurement. Since it is consensus in the gravitational-wave community that vacuum fluctuations contribute to the noises in the detectors, we also clarify the contributions of vacuum fluctuations to the quantum noise spectral density without using the two-photon formulation which is used in the gravitational-wave community. We found that the conventional noise spectral density in the two-photon formulation includes vacuum fluctuations from the main interferometer but does not include those from the local oscillator. Although the contribution of vacuum fluctuations from the local oscillator theoretically yields the difference between the above two models in the noise spectral densities, this difference is negligible in realistic situations.

Consequences of Quantum Noise Control for the Relaxation Resonance Frequency and Phase Noise in Heterogeneous Silicon/III-V Lasers

We have recently introduced a new semiconductor laser design which is based on an extreme, 99%, reduction of the laser mode absorption losses. This was achieved by a laser mode design which confines the great majority of the modal energy (> 99%) in a low-loss Silicon guiding layer rather than in highly-doped, thus lossy, III-V p+ and n+ layers, which is the case with traditional III-V lasers. The resulting reduced electron-field interaction leads directly to a commensurate reduction of the spontaneous emission rate by the excited conduction band electrons into the laser mode and thus to a reduction of the frequency noise spectral density of the laser field often characterized by the Schawlow-Townes linewidth. In this paper, we demonstrate theoretically and present experimental evidence of yet another major beneficial consequence of the new laser design: a near total elimination of the contribution of amplitude-phase coupling (the Henry α parameter) to the frequency noise at “high” frequencies. This is due to an order of magnitude lowering of the relaxation resonance frequency of the laser. The practical elimination of this coupling enables yet another order of magnitude reduction of the frequency noise at high frequencies, resulting in a quantum-limited frequency noise spectral density of 130 Hz2/Hz (linewidth of 0.4 kHz) for frequencies beyond 680 MHz. This development is of key importance in the drive to semiconductor lasers with higher coherence, particularly in the context of integrated photonics with a small laser footprint.

Suppression of correlated interference by adaptive notch filters under pulse repetition period modulation

Introduction: We discuss the problem of correlated noise suppression by adaptive complex notch filters of various orders. In order to eliminate the dependence of the transmission coefficient of the useful signal on its frequency, the pulse repetition period is modulated. Purpose: Studying the influence of pulse repetition period modulation on the correlated noise suppression coefficient. Methods: The notch filter parameters were optimized with the criterion of minimum average dispersion of correlated noise at the output of the filters during the repetition period modulation. Results: Expressions are obtained for the variance of correlated noise at the output of complex adaptive filters of various orders when the repetition period is modulated. Relationships are given for finding the optimal values ​​of the tuning frequency and coefficients of the notch filters which minimize the correlated noise level at their output. Expressions are obtained for the coefficients of correlated noise suppression by notch filters in the context of pulse repetition period modulation. The graphs are presented showing how the correlated noise suppression coefficient depends on the relative value of the probing signal repetition period deviation for various values ​​of the correlated noise spectral density width at optimal or non-optimal values ​​of the tuning frequency and coefficients of the notch filters. It is shown that the use of probing pulse repetition period modulation leads to a decrease in the correlated noise suppression coefficient. On the other hand, the adaptation of the weighting coefficients for the adopted models of notch filters and correlated interference provides an increase in the suppression coefficient. Practical relevance: When developing or studying correlated noise suppression systems, the obtained results make it possible, taking into account the permissible losses of the suppression coefficient, to reasonably choose the input pulse repetition period deviation value in order to eliminate the effect of “blind” frequencies.