Direct Digital-to-RF Conversion for Mobile-Phone Basestation Applications using Bandpass Sigma Delta Modulation
نویسندگان
چکیده
Sigma-delta modulator based digital-to-analog converters (DAC) have offered low-frequency designers a highly linear, high resolution data converter architecture that is highly amenable to integration with complex digital systems. Increasingly these data converters have been used to deliver all the power needed. In wireless applications, it is increasingly desirable to apply low-frequency sigma-delta techniques to RF signals and try to achieve similar benefits. In this paper we discuss the unique challenges that DACs in mobile phone basestations must satisfy and we present a flexible bandpass sigmadelta modulator architecture that can satisfy these criteria.
منابع مشابه
BandPass Sigma-Delta Modulator for wideband IF signals
Sigma-Delta modulation techniques have been applied to narrow-band passband signals [Jantzi93]. Recent technology improvement has allowed conversion of GSM channels [Ong97] and DECT channels[Bazarjiani97]. In this report, the main concept behind BandPass Sigma-Delta conversion is briefly explained together with its advantages and applications. The architecture choices for this design are then d...
متن کاملDecimation for Bandpass Sigma-Delta Analog-to-Digital Conversion
An efficient means for constructing a narrow bandpass filter for an analogto-digital converter based on a bandpass sigma-delta modulator is presented. It is shown that the filter can be made with very simple hardware, comparable to that required by an analog-to-digital converter using standard lowpass sigma-delta modulation. Introduction Bandpass sigma-delta modulation [1] is a variant of the m...
متن کاملApplications of Polyphase Filters for Bandpass Sigma-delta Analog-to-digital Conversion
The traditional lowpass Sigma-Delta (Σ∆) based Analog-to-Digital (A/D) conversion principle has been recently extended to bandpass for direct IF conversion. Such converter offers high Signal-to-Noise (SNR) ratios for narrowband signals relative to the sampling frequency, at significantly lower oversampling ratios in comparison to the conventional lowpass Σ∆ converters. In this paper a sixth-ord...
متن کاملA 3-30 MHz Tunable Continuous-Time Bandpass Sigma-Delta A/D Converter for Direct Conversion of Radio Signals
modulators are still limited to IFs of several tens of megahertzs [6], [9]. The disadvantages of the CT approach are less accuracy and lower dynamic range. Abstract— In this paper we present the design and simulation results of a CMOS fourth-order bandpass deltasigma modulator, intended for the A/D conversion of RF signals directly coming from a shortwave receiver antenna. The modulator tuning ...
متن کاملDelta-Sigma Digital-RF Modulation for High Data Rate Transmitters
A low power, wideband wireless transmitter utilizing ∆Σ direct digital modulation of an RF carrier is presented. The transmitter architecture replaces high dynamic range analog circuits with high speed digital circuits and a passive LC bandpass filter, saving power and area compared to conventional IQ modulators for wideband systems. A prototype transmitter IC built in 0.13 μm CMOS demonstrates...
متن کامل