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We present a dual-mode receiver for dual-band CDMA 2000 cellular radio, which incorporates an integrated GPS signal path for "E911" emergency call location requirements. The highly integrated zero-IF architecture has separate optimised front-ends, but employs a single shared, reconfigurable baseband path for the two signal bandwidths. The CDMA LO s...
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... system block diagram is shown in Figure 1. The ZIF signal flow is now well established, and is used for both paths. ...
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The DECT (Digital Enhanced Cordless Telecommunications) standard is a member of the IMT-2000 family and the 3 rd Generation (3G) DECT physical layer provides multi-level modulation capability enabling 2 Mbps services. In this paper, we present a receiver implementation for this new physical layer. The receiver is based on a coherent I-Q demodulator...
Citations
... The first source for IM2 degradation is device mismatch [2] that can be efficiently corrected by adding auxiliary calibration [3]- [6]. Another major source is device non-linearity, due for instance to the quadratic I(V) law of a MOSFET transistor, which can down-convert continuous-wave (CW) and amplitude-modulated (AM) blockers directly to DC or near DC causing signal-to-noise ratio (SNR) deterioration (Fig. 1). ...
... The trend towards higher number of frequency bands also increases local-oscillator (LO) to RF-input leakage in many ways. This could come from the larger number of used LC-oscillators [5] but also from the LO frequency-translation circuits based on multiple mixing and LC-filtering operations [6]. Leakage could result from conducted injections through the substrate, parasitics or supply lines, but it might also be related to magnetic coupling between the LO generation and the frontend blocks through the low-noise-amplifier (LNA) and the mixer. ...
... The proposed solution also involves zero added power consumption and negligible noise deterioration. The relative advantages have been proven on a zero-IF CDMA receiver implemented in 0.25 μm BiCMOS technology and operating in the PCS 1960 MHz band with 20 dB to 25 dB improvement for both LO-to-RF isolation and IIP2 parameters [6]. ...
To achieve a high IIP2 level on a mixer, static calibration techniques have been developed. Most of them are based on an intentional introduction of a calibrated mismatch in the structure of the mixer. They are performed at production stage. It is also possible to automate them but their activation is strongly limited in portable devices because of system restrictions. Furthermore, IIP2 is sensitive to system variations, thereby degrading the calibration operation. The challenge is so to make the calibration system dynamic, i.e. performing an online calibration. This paper presents a perturbance-based algorithm as part of an automatic calibration system to track the optimum IIP2 level. Measurements validate the algorithm behavior and indicate the feasibility of using it in a complete calibration system for a future on-chip implementation.
