No abstract

A subsampling filter is proposed for a discrete-time receiver (DTR). This filter achieves signal discretisation, filtering and downconversion simultaneously. With the proposed subsampling filtering technique, the subsampling mixer in a conventional DTR is eliminated, which can reduce power, cost and noise. The first 2.4 GHz DTR prototype for Zigbee application is fabricated in a 0.18 μm CMOS process. It achieves 23 dB conversion gain, 17.6 dB noise figure and −15 dBm IIP3. Operated from a single 1 V supply, the low-noise amplifier and following filter stages consume only 3.8 mW and the total receiver power consumption is 25.6 mW.

This paper presents a digital background linearization technique for VCO-based delta-sigma ADC. The nonlinearity of the VCO in the main ADC is mitigated with the aid of the reference OP-based delta-sigma ADC and the digital least-mean square (LMS) correction algorithm. The reference ADC provides sufficient linearity performance as the calibration reference to form an inverse transfer function of the nonlinear voltage-to-frequency characteristic while the LMS-based calibration scheme shortens the correction time to reduce energy consumption. The simulated SFDR/SNDR of 70.2 dB/62.7 dB over a bandwidth of 10 MHz is achieved, which is 23.3 dB/16.6 dB better than the SFDR/SNDR of uncalibrated ADC. A prototype first-order VCO-based ADC is designed in 90-nm CMOS process and dissipates 2.89 mW from a supply voltage of 1.2 V.

A wideband magnitude and phase concurrent correction technique (MPCCT) is proposed in this paper. The MPCCT can concurrently correct the gain and phase imbalances between the differential signals of an active balun. This technique employs positive feedback and negative feedback as correction circuits. The two feedback loops redistribute the gain and phase imbalances into the differential outputs equally. The balun using MPCCT has the measured maximum gain 6.1dB at 59 GHz while the gain and phase imbalances are 0.14 dB and 0.7° respectively. The bandwidth of the balun is 12 GHz. The measured results demonstrate the robust correction at millimeter-wave (MMW) frequency. The power consumption is 11.6mW with 1V supply voltage and the chip area is 0.26 mm 2 excluding the pads.

No abstract