A 2.7 V 2.5 GHz bipolar chipset for digital wireless communication

Delta-sigma data conversion in wireless transceivers

“…One is based on open-loop VCO modulation, and the other is based on fractional-synthesis. An example of a commercial transmitter that uses the open-loop VCO modulation technique is presented in [52] and [53], in this case for a DECT cordless telephone. Between transmit bursts, the desired center frequency is set relative to a reference frequency by enclosing the VCO within a conventional analog PLL.…”

Highly integrated RF-IC's for GSM and DECT systems-A status review

“…Also, the total component count for the RF front end moved from 400-500 down to 200-300, with further potential to around 100 components or less. Also, since 1995, complete handhelds using 2.7 V for the complete RF function without the PA have been available [3], [7], [8], [17].…”

“…1) single conversion to one IF of 40-130 MHz followed by a conversion to I/Q-Baseband [1], [2]; some years later IF frequencies between 250-450 MHz were introduced [3], [8]; 2) dual conversion with two IF-frequencies, followed by a subsampling A/D conversion; 3) dual conversion with two IF-frequencies, follwed by a phase comparator and a RSSI evalution; 4) homodyn concept with direct conversion to I/Q Baseband [13], [15]; 5) that direct A/D conversion or subsampling for low power application is still not in use and a dream of the future.…”

Continuous Phase Modulation of F-QPSK-B Signals

“…Furthermore, an additional power amplifier is not necessary when the carrier produced by the RF local oscillator is directly modulated at the desired transmit power level [6]. For these reasons, the CPM scheme is used to implement many lowcomplexity, low-cost, and low-power consumption transmitters, such as Bluetooth [2], [7] and DECT [8], [9]. There has also been an increasing need for both power and spectrum efficient modulation techniques for telemetry systems.…”