A low-power third-order ΔΣ modulator using a single operational amplifier
An architecture for low-power ΔΣ modulators suitable for high-resolution portable sensor systems is presented. The circuit uses a single operational amplifier to achieve a third-order noise shaping. The two-stage op-amp employs a boosting technique that increases by 5 the slew-rate. The circuit, simulated at the transistor level using a conventional 0.18-µm CMOS technology, obtains a peak SNDR of 88 dB over an input signal bandwidth of 100 kHz. The simulated power consumption is 125 µW with a 1.5-V supply voltage. The achieved Figure of Merit (FoM) is 31 fJ/conversion-level.
Noise-shaped multbit D/A convertor employing unit elements
By appropriately selecting the elements used to form each output sample of a multibit digital-to-analogue convertor, the spectrum of the error caused by element mismatch can be noise-shaped. Simulations indicate that first-order, second-order and bandpass noise-shaping are all possible. The technique enables the use of multibit feedback in delta-sigma A/D and D/A convertors.
DVB-H and IP Datacast—Broadcast to Handheld Devices
DVB-H (Digital Video Broadcasting-Handheld) is the digital broadcast standard for transmitting broadcast content to handheld terminal devices, developed by the International DVB (Digital Video Broadcasting) Project. DVB-H is based on the DVB-T standard for digital terrestrial television but tailored to the special requirements of the pocket-size class of receivers. The IP Datacast specification, which was also recently standardized, contributes the higher layer protocols to build a complete end-to-end system. This article presents an overview of the DVB-H and IP Datacast systems with respect to features and technology. An outlook on DVB-H network deployment is given