Analog-to-digital converters and their applications in radio receivers

Abstract-Analog-to-digital converters (ADC's) are ubiquitous, critical components of software radio and other signal processing systems. This paper surveys the state-of-the-art of ADC's, including experimental converters and commercially available parts. The distribution of resolution versus sampling rate provides insight into ADC performance limitations. At sampling rates below 2 million samples per second (Ms/s), resolution appears to be limited by thermal noise. At sampling rates ranging from 2 Ms/s to 4 giga samples per second (Gs/s), resolution falls off by 1 bit for every doubling of the sampling rate. This behavior may be attributed to uncertainty in the sampling instant due to aperture jitter. For ADC's operating at multi-Gs/s rates, the speed of the device technology is also a limiting factor due to comparator ambiguity. Many ADC architectures and integrated circuit technologies have been proposed and implemented to push back these limits. The recent trend toward single-chip ADC's brings lower power dissipation. However, technological progress as measured by the product of the ADC resolution (bits) times the sampling rate is slow. Average improvement is only 1.5 bits for any given sampling frequency over the last six-eight years.Index Terms-Analog-to-digital converters, aperture jitter, comparator ambiguity, input-referred noise, signal-to-noise ratio, spurious-free dynamic range.

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“…These are the fastest bandpass modulators yet built. Further discussion of bandpass sampling for RF applications can be found in [2].…”

Section: High-performance Adc Architecturesmentioning

confidence: 99%

“…The effective number of bits associated with SFDR is (2) SFDR is the ratio of the single-tone signal amplitude to the largest nonsignal component within the spectrum of interest. Fig.…”

Section: Adc Characterizationmentioning

confidence: 99%

Analog-to-digital converter survey and analysis

Walden

1999

IEEE J. Select. Areas Commun.

1,839

959

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“…Other characteristics of the ADCs that become important when they are used beyond the Nyquist rate or with undersampling have been studied in the literature [13]; one of the most relevant is the degradation of the signal to noise ratio (SNR). Even under ideal conditions (meaning among other things that the signal has been perfectly band-pass filtered before the conversion stage), there is a quantization error whose spectrum extends well beyond the Nyquist frequency f s ( f s =2B, being B the signal bandwidth).…”

Section: Noise Considerationsmentioning

confidence: 99%

“…Even under ideal conditions (meaning among other things that the signal has been perfectly band-pass filtered before the conversion stage), there is a quantization error whose spectrum extends well beyond the Nyquist frequency f s ( f s =2B, being B the signal bandwidth). When a quantized signal is sampled, the entire quantization noise spectrum is folded back into the baseband (aliasing), and it is reasonable to take the total quantization noise power as a measure of the noise to be expected in the baseband [13,18]. For sinusoidal inputs, an expression for the maximum theoretical signal to quantization noise ratio at the Nyquist rate can be derived following certain assumptions about the noise and the input signal [19,20]:…”

Section: Noise Considerationsmentioning

confidence: 99%

“…Therefore, undersampling can be used to move the spectrum to a lower frequency (demodulate), functioning like a mixer. The original RF signal information can be completely recovered from those sampled values if the signal is actually a bandpass signal and the process of sampling satisfies the bandpass sampling theorem [12,13]. Then, the undersampling procedure directly applied to the amplified NMR or MRI signal as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Potential use of the undersampling technique in the acquisition of nuclear magnetic resonance signals

Pérez¹,

Santos²,

Vaquero

2001

MAGMA

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This communication reviews the use of undersampling techniques to acquire NMR signals. Undersampling transforms bandpass free induction decay (FID) signals, centered at high frequencies, into lowpass signals or bandpass signals centered at much lower frequencies. Consequently, the analog electronic stages that perform the demodulation can be eliminated, gaining in stability and reducing the phase distortion while maintaining an equivalent or better signal to noise ratio when an adequate sampling rate is chosen. The technique has been tested on a BRUKER BIOSPEC BMT 47/40, and the results show that undersampling could be used to process NMR and MRI signals, extending the range of applications of the 'digital radio' techniques to NMR and MRI apparatus.

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Transceivers

Dominique

1999

Wiley Encyclopedia of Electrical and Electronics Engineering

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Analog-to-digital converters and their applications in radio receivers

Cited by 166 publications

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Analog-to-digital converter survey and analysis

Analog-to-digital converter survey and analysis

Potential use of the undersampling technique in the acquisition of nuclear magnetic resonance signals

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