High performance and energy efficiency are very crucial aspects in e.g. the field of edge computing where a tight power budget constrains the device operation. Different logic families were explored ...over the years to design standard cells with higher performance and/or lower power while keeping the noise immunity and the compatibility with design automation tools intact. Hybrid pass transistor logic with static CMOS output (HPSC) seems to be promising and is exploited in this paper to design low energy, high performance and toolchain-compatible standard cells without compromising on noise immunity and chip area. This paper presents a 2/3-input XOR cell, a 2/3-input XNOR cell, two variants of a half adder cell, a full adder cell and two variants of a 1-bit multiply-accumulate combinational cell based on a combination of HPSC and static CMOS logic in a commercial 65nm Low-Power CMOS technology. Post-layout simulations over all the process-voltage-temperature corners show a 4.7% - 35.7% lower energy-delay product with significant improvement in the propagation delay of the proposed cells.
An integrated spectrum analyzer is useful for built-in self-test purposes, software-defined radios, or dynamic spectrum access in cognitive radio. The analog/RF performance is impaired by a number of ...factors, including thermal noise, phase noise, and nonlinearity. In this paper, we present an integrated circuit with two integrated RF-frontends, of which the outputs are crosscorrelated in digital baseband. We show by theory and measurements that the above-mentioned impairments are mitigated by this technique. The presented 65-nm CMOS prototype operates at 1.2 V, and obtains a noise floor below -169 dBm/Hz, an IIP 3 of +25 dBm, and more than 20 dB of phase-noise reduction. In a special high-impedance mode, an even lower noise floor below -172 dBm/Hz is obtained.
Cross-correlation can be used in energy detection applications, such as spectrum analyzers, but also frequency shift keying (FSK) receivers, to improve noise suppression. To achieve higher ...signal-to-noise ratio (SNR), integration in time may be used, but could make it rather slow for communication purposes. In order to achieve better data-rates in low SNR conditions, we propose to use multiple chains instead of the traditional two chains. In this paper, we show an analysis of the SNR improvement and the power consumption penalty for BFSK modulation when using more chains. It shows that for low noise correlation between the chains, the improvement in sensitivity is proportional to the number of chains. Also, we develop a figure-of-merit to evaluate the optimum number of chains for different parameters of the receiver design. Furthermore, two examples from literature are analyzed. At their optimum number of chains, they both show ~6dB improvement in sensitivity with similar or even better figure-of- merit.
Spurious-Free Dynamic Range of a Uniform Quantizer Oude Alink, M.S.; Kokkeler, A.B.J.; Klumperink, E. ...
IEEE transactions on circuits and systems. II, Express briefs,
06/2009, Letnik:
56, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Quantization plays an important role in many systems where analog-to-digital conversion and/or digital-to-analog conversion take place. If the quantization error is correlated with the input signal, ...then the spectrum of the quantization error will contain spurious peaks. Although analytical formulas describing this effect exist, numerical evaluation can take much effort. This brief provides approximations for the spurious-free dynamic range (SFDR) of a uniform quantizer with a single sinusoidal input, with and without additive Gaussian noise. It is shown that the SFDR increases by approximately 8 dB/bit, in case there is no noise. Generalizing this result to multitone inputs results in an additional 2 dB/bit per additional tone. Additive Gaussian noise decorrelates the sinusoid(s) and the quantization error, which results in a dramatic increase in SFDR.
Harmonic downmixing may cause a spectrum sensing device to erroneously flag parts of the spectrum as occupied. Receivers employing harmonic rejection (HR) rarely obtain more than 60 dB of HR, which ...may not be enough for spectrum sensing for dynamic spectrum access. We improve HR by employing two RF-receivers, integrated in a single 65nm CMOS IC, and using a small offset in their LO-frequencies. The offset is corrected in the digital baseband, after which the final receiver outputs are crosscorrelated. Our measurements show that the HR can be significantly improved without calibration or time penalty, even for high initial HR, but that the improvement is limited by crosstalk between the receivers.
In the receiver path and in spectrum analyzers, typically gain control blocks are used to limit the incident power to the level that the receiver circuitry can handle without degrading the linearity; ...in the transmitter path stringent power control is also desirable. Although variable-gain amplifiers (VGAs) traditionally implement the gain-control block, attenuators based on FET transistors show superior performances on linearity, power handling capability and power consumption.
Spectrum sensing is one of the key characteristics of a cognitive radio. Energy detection provides maximum flexibility by not relying on any prior knowledge, but suffers from an SNR-wall due to noise ...uncertainty. Crosscorrelation of the outputs of two receiver paths is a technique to reduce the noise level of the total receiver, and hence improves the SNR. The reduction of the noise is limited by correlated noise originating from shared components near the antenna. In this paper we explore the use of a separate antenna for each receiver for crosscorrelation spectrum sensing. One immediate advantage is that due to the removal of the splitter, which was necessary to interface the single antenna to two receivers, the SNR improves, significantly reducing the required measurement time. A lot of the noise correlation can be removed, leading to a lower residual noise floor. The noise at each antenna will still be partially correlated due to mutual coupling, spatial noise correlation and man-made noise. We show that some signal power can be lost in the sensing process due to partial decorrelation of the signal at the two antennas. Fortunately, this seems to be a problem only in highly mobile environments, which makes the use of two-antenna crosscorrelation spectrum sensing an interesting solution towards more reliable energy detection.
A dual RF-receiver preceded by discrete-step attenuators is implemented in 65nm CMOS and operates from 0.3-1.0 GHz. The noise of the receivers is reduced by cross-correlating the two receiver outputs ...in the digital baseband, allowing attenuation of the RF input signal to increase linearity. With this technique a displayed average noise level below -169 dBm/Hz is obtained with +25 dBm IIP 3 , giving a spurious-free dynamic range of 89 dB in 1 MHz resolution bandwidth.
Wireless sensor networks have recently emerged in a wide range of applications. Many attributes are essential for such networks such as: low cost, small form-factor, limited peak power consumption ...and the ability to operate in harsh interference scenarios. Most of these networks do not require high data-rates to operate. In this respect, sub-sampling receivers have shown promising results but suffer from noise folding and interference aliasing. In this paper, a sub-sampling receiver in combination with cross-correlation is used to enhance sensitivity and interference robustness while maintaining the sub-sampling advantages. An architecture which uses two different sampling frequencies is proposed. It shows ∼2dB SNR improvement compared to traditional architectures due to cross-correlation and an additional ∼2dB for each doubling of integrations. For a BER of 10- 3 , the required SIR is reduced with 4.5dB, 11.5dB and 14.5dB after using cross-correlation with the same, half and quarter data-rate used respectively. These improvements allow for a lower-power and lower-cost implementation.
Presence of minimal residual disease (MRD), detected by flow cytometry, is an important prognostic biomarker in the management of B‐cell precursor acute lymphoblastic leukemia (BCP‐ALL). However, ...data‐analysis remains mainly expert‐dependent. In this study, we designed and validated an Automated Gating & Identification (AGI) tool for MRD analysis in BCP‐ALL patients using the two tubes of the EuroFlow 8‐color MRD panel. The accuracy, repeatability, and reproducibility of the AGI tool was validated in a multicenter study using bone marrow follow‐up samples from 174 BCP‐ALL patients, stained with the EuroFlow BCP‐ALL MRD panel. In these patients, MRD was assessed both by manual analysis and by AGI tool supported analysis. Comparison of MRD levels obtained between both approaches showed a concordance rate of 83%, with comparable concordances between MRD tubes (tube 1, 2 or both), treatment received (chemotherapy versus targeted therapy) and flow cytometers (FACSCanto versus FACSLyric). After review of discordant cases by additional experts, the concordance increased to 97%. Furthermore, the AGI tool showed excellent intra‐expert concordance (100%) and good inter‐expert concordance (90%). In addition to MRD levels, also percentages of normal cell populations showed excellent concordance between manual and AGI tool analysis. We conclude that the AGI tool may facilitate MRD analysis using the EuroFlow BCP‐ALL MRD protocol and will contribute to a more standardized and objective MRD assessment. However, appropriate training is required for the correct analysis of MRD data.
PDF
