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A Quadrature Bandpass Modulator for Digital Radio
 ISSCC Dig. Tech. Papers
, 1997
"... Abstract—A quadrature bandpass modulator IC facilitates monolithic digitalradioreceiver design by allowing straightforward “complex A/D conversion ” of an imagereject mixer’s I and Q outputs. Quadrature bandpass modulators provide superior performance over pairs of real bandpass modulator ..."
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Abstract—A quadrature bandpass modulator IC facilitates monolithic digitalradioreceiver design by allowing straightforward “complex A/D conversion ” of an imagereject mixer’s I and Q outputs. Quadrature bandpass modulators provide superior performance over pairs of real bandpass modulators in the conversion of complex input signals, using complex filtering embedded in loops to efficiently realize asymmetric noiseshaped spectra. The fourthorder prototype IC, clocked at 10 MHz, converts narrowband 3.75MHz I and Q inputs and attains a dynamic range of 67 dB in 200kHz (GSM) bandwidth, increasing to 71 and 77 dB in 100 and 30kHz bandwidths, respectively. Maximum signaltonoise plus distortion ratio (SNDR) in 200kHz bandwidth is 62 dB. Power consumption is 130 mW at 5 V. Die size in a 0.8m CMOS process is 2.4 1.8 mm2. Index Terms—Analogdigital conversion, CMOS analog integrated circuits, complex filters, digital radio, bandpass sigma– delta modulation, switchedcapacitor circuits. I.
CHARGEDOMAIN SAMPLING OF HIGHFREQUENCY SIGNALS WITH EMBEDDED FILTERING
"... Academic Dissertation to be presented with the assent of ..."
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Academic Dissertation to be presented with the assent of
Metastability Determines The Noise In Fast And Accurate A/D Converters
"... : We have investigated metastability errors in algorithmic A/D converters. When the input signal is inside a window, V M , a metastability errors appear as a spike in the output code. These errors looks like white noise in the frequency domain, and can therefore be compared with the quantization n ..."
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: We have investigated metastability errors in algorithmic A/D converters. When the input signal is inside a window, V M , a metastability errors appear as a spike in the output code. These errors looks like white noise in the frequency domain, and can therefore be compared with the quantization noise. For an nbit ADC, the probability of a metastability error in bit j is p Mj = V M 2 (nj) , error amplitude is A Mj = 2 (j2) , and power contribution from these errors is P = V M 2 (n4) (2 (n+1)  2). For a metastability noise less than the quantization noise the relation V M < V Q /(2 (n1) 3), where V Q is the quantization step, has to be fulfilled. The metastability problem determines the speed and gain requirements on the comparator. The relations are validated with measurements and simulations of an SAADC. A method for detecting and correcting these errors is indicated. Keywords: Metastability, Algorithmic A/D converter, SignaltoNoiseRatio. 1. INTRODU...