Josef Fenk

Linearity considerations of W-CDMA front-ends for UMTS

The signals used in UMTS have wide bandwidth and high crest factors. Circuit designers use sinusoids to design and simulate their building blocks. Formulas are presented relating the various distortion effects of the W-CDMA signals like adjacent channel leakage ratio (ACLR), cross modulation or intermodulation to well-known linearity measures like input intercept point of third-(IIP3) and second-order (IIP2) and compression point. Measurements of amplifiers with sinusoidal and broadband signals confirm the obtained results.

Fast and accurate ramp generation with a PLL-stabilized 24-GHz SiGe VCO for FMCW and FSCW applications

In Microwave sensor systems the application of linear frequency modulation schemes as well as frequency stepping is commonly used. In this paper we describe the generation of fast and highly accurate frequency ramps by means of a fractional-N-PLL stabilized integrated 24-GHz voltage controlled SiGe oscillator, which are a prerequisite for high achievable measurement accuracies. Linearity measurements with phase evaluation on fabricated devices have shown an RF-phase deviation of less than 1.5 rad for a linear frequency sweep with a bandwidth of 250 MHz at 24.5 GHz and a sweep duration of 250 /spl mu/s.

A 2.7 V 800 MHz-2.1 GHz transceiver chipset for mobile radio applications in 25 GHz f/sub t/ Si-bipolar

A 800 MHz-2.1 GHz, 2.7 V transceiver chipset for mobile radio which includes transmitter with direct conversion quadrature modulator, IF and RF frequency synthesizing, receiver with LNA, mixer, programmable 80 dB-IF-amplifier and quadrature demodulator Is reported. The /spl sim/4 mm/sup 2/, 25 GHz f/sub t/ bipolar chips consume <250 mW.

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

TDMA based digital systems like GSM for cellular and DECT for cordless application have created an increasing market within Europe and gained widespread acceptance also outside Europe. This paper gives an overview of both systems, The system requirements and their influences on highly integrated RF ICs for GSM and DECT are discussed in detail. The various trends of progresses in integration of both systems will be shown, with the different advantages and the disadvantages of the concepts in use. The challenges of increasing the level of integration and an outlook to future will be presented.

A bipolar upconversion modulation loop transmitter for dual-band mobile communications

This paper presents design considerations and measurement results of an upconversion modulation loop transmitter IC (PMB 2255) implemented in Siemens 26 GHz Si bipolar technology B6HF. The device consists of a vector modulator, downconversion mixer, a modulation phase-locked loop (PLL) and a three-wire programming bus. Besides power-down and standby modes, added values of switchable filter cutoff frequency and precharge function are also realized for dual- and multi-band digital mobile communication systems such as GSM900, GSM1800 and GSM1900. Based on measurements the device provides an excellent performance in designed intermediate frequency range from 300 to 550 MHz with supply voltage from 2.7 to 4.5 V, ambient temperature from -30 to 85/spl deg/C, and local and RF frequencies up to 2.0 GHz.

A single-chip Si-bipolar 1.6-GHz VCO with integrated-bias network

A single-chip 2.7-V voltage-controlled oscillator (VCO) with an integrated-bias network has been implemented in an Si-bipolar process with an f/sub T/ of 25 GHz. With an on-chip resonator consisting of vertically coupled inductors and varactor diodes, an oscillation frequency of 1.56 GHz was measured. A careful design of the oscillator and bias network was necessary to achieve a phase noise performance of -139 dBc/Hz at 4.7 h MHz off carrier. The tuning sensitivity was 100 MHz/V, which is sufficient to compensate for production tolerances. The VCO can be used as a building block for single-chip transceivers in digital European cordless telephone or global system for mobile communication systems.

FN-modulation loop architecture for fully integrated 1 Mb/s GFSK transmitter

A low cost GFSK transmitter architecture is investigated for its sensitivity to parameter variation in mass production. In this paper the simulation results for a system design, based on certain specifications, are presented and the effects of mismatch in the open loop gain are demonstrated. It is shown that the system specifications can be met if the open loop gain error is less than 8% of the nominal value.

VHF/UHF Modulator IC

The home TV is evolving more and more as a communication center for all home communications services. The development of this new integrated circuit was based on the increasing demand for additional TV signal sources. The design of a single chip VHF / UHF modulator IC with excellent performance and minimized external circuitry is described in this paper. This integrated circuit has been developed to convert audio and video signals into high frequency VHF / UHF-TV signals for all TV standards. It is suitable for applications in video recorders, personal computers, cable converters, remodulators, video test signal generators, and radio amateur TV transmitters.