Analog Channel Filter Design, The Rf Receiver

With the development of wireless communication, it becomes realistic to integrate different communication protocols on one chip. The main purpose of this paper is to design a programmable low pass filter, which can be applied to cover different protocols of DVB Tuner. Based on this purpose, a lot of work about theoretic research and circuit implement are carried out.Firstly, this paper focus on the basic theory of filter design, analyses the principles and problems in Active-RC filter and Gm-C filter. The filter function implement, synthesis and integrator design are discussed.Secondly, the specification of Noise Figure and Linearity are analyzed from the consideration of DVB Tuner application, the other performance specification of filter are also be defined in the later.And then, a programmable 8th order Active-RC filter for DVB Tuner applications with automatic frequency tuning (AFT) is presented in this paper. The filter is implemented in Butterworth biquad structure. The AFT circuit is introduced to compensate the frequency variation by a 6-bit switched-capacitor array, and the switched-resistor array is adopted to cover different cut-off frequencies.Later, a novel digital controlled low noise Bandgap voltage reference is proposed in this paper. The adjustable voltage reference and temperature coefficient is implemented by controlling the number of PNP transistors, the noise contribution and optimization of Bandgap are given. To obtain a low noise supply voltage for RF VCO, another low noise, high PSR LDO circuit using Noise filter and PSR cancellation stage is proposed. The post-simulation dedicates the perfect noise and PSR performance can be achieved.Finally, the PCB considerations and measurement results are given, which justify the design principle and methodology.