Imaging systems based on millimeter waves (mm-waves) are advancing to achieve higher resolution and wider bandwidth. However, a large bandwidth requires high sample rates, which may limit the development of ultra-wideband imaging systems. In this letter, we introduce concept frequency diverse array (FDA) into mm-wave particular, propose an method FDA configuration reduce sampling rates. propose...

This paper proposes a column-wise two-step SingleSlope (SS) ADC, which improves the sampling rate while maintaining the architecture of the conventional SS-ADC for high-speed CIS. To remove the problem of missing code in multi-stage structures, occurring on every boundary between steps of the coarse ADC, the range of the fine ADC is doubled to cover the boundary. The sampling rate of the ADC is...

This paper describes a new firstand second-order delta-sigma modulator concept where the first integrator is extracted and implemented by a frequency modulator with the modulating signal as the input. The result is a simple delta-sigma modulator with no need for digital-to-analog converters, allowing straight-forward multi-bit quantization. Without the frequency modulator, the circuit becomes a...

An image-rejected multi-band frequency down-conversion scheme is proposed and experimentally demonstrated based on photonic sampling. The radio-frequency (RF) signals to be processed are copied into two replicas in quadrature, which then sampled by an ultra-short optical pulse train via a polarization-multiplexed modulator. After polarization demultiplexing detection using pair of low-speed pho...

We present an inexpensive multi-protocol communication system implemented entirely in software comprised of Global Positioning System (GPS), Wireless Local Area Network (WLAN) and Bluetooth (BT). All three communications protocols share the same Analog to Digital converter and are sampled at the same hardware sampling rate. The hardware sampling clock is provided by a high stability crystal osc...

We discuss a technique for mapping the synchrotron turnover frequency distribution using nearly simultaneous, multi–frequency VLBI observations. The limitations of the technique arising from limited spatial sampling and frequency coverage are investigated. The errors caused by uneven spatial sampling of typical multi– frequency VLBA datasets are estimated through numerical simulations, and are ...