1 Abstract—In [1], we have shown that it is feasible to design filters with arbitrary waveform responses and therefore we propose an ultra-wideband pulse generator incorporating a filter with a Daubechies’ impulse response (i.e. maximally flat over the desired frequency range). This pulse generator is co-designed with wideband antennas. An eight-order Padé approximation of its transfer function is selected to implement the FCC stipulated frequency spectrum. Subsequently, the orthonormal [2] form is adopted, which is intrinsically semi-optimized for dynamic range, has low sensitivity to component mismatch, high sparsity and whose coefficients can be physically implemented. Each coefficient in the state-space description of the orthonormal ladder filter is implemented at circuit level using a novel 2-stage gm cell employing negative feedback. Simulation results in IBM’s CMOS 0.13μm technology show that this pulse generator requires a total current of 25mA from a 1.2V power supply. The frequency coverage of the simulated waveform is about 85% of the FCC mask. Index Terms–analog integrated circuits, Daubechies’ wavelets, filter approximation, low power, state-space description, impulse radio, ultra-wideband I. INTRODUCTION Ultrawideband (UWB) technology has gained much interest during the last few years as a potential candidate for future wireless short-range data communication. A particular type of UWB communication is impulse radio, where very short transient pulses are transmitted rather than a modulated carrier. The United States Federal Communications Commission (FCC) has officially endorsed ultra-wideband technology for commercial wireless applications. Although impulse radio ultra-wideband technology promises enhanced data throughput with low-power consumption, it inseparably introduces several challenging design issues. The FCC allocated spectrum for UWB lies from 3.1-10.6GHz. As ultra- wideband systems transmit at very low spectral densities and occupy a large amount of bandwidth, it thus is unequivocal that the pulse generator’s performance be optimized for maximum energy efficiency. In literature, it is seen that one of the most attractive qualities of Daubechies’ wavelets [3] is that they are window-like functions in the frequency domain. This single characteristic accounts for their S. Bagga, S. A. P. Haddad, Wouter A. Serdijn and John R. Long are with the Electronics Research Laboratory, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628CD, Delft, The Netherlands (e-mail: {s.bagga, s.haddad, w.a.serdijn, j.r.long}@ewi.tudelft.nl). unique localization property and therefore the Daubechies’ wavelet can be used as the transmitted waveform in impulse radio UWB. In Figures 1a and 1b show the mother wavelet and the scaling function of order 8, where the latter is often used to generate the mother wavelet. a) Mother Wavelet b) Scaling Function Fig. 1 Daubechies’ Scaling and Mother Wavelets Like in [1], a transfer function whose impulse response approximates either the scaling or the mother wavelet can be generated. As Daubechies’ wavelet functions are designed to have large number of zero crossings, for the simplification in numerical computation, the scaling function is chosen, which has fewer zero crossings. This property facilitates the transfer function design synthesis. In this paper we propose an FCC compliant pulse generator for impulse radio ultrawideband communications. A system model is An FCC Compliant Pulse Generator for IR-UWB Communications S. Bagga, S. A. P. Haddad, W. A. Serdijn and J. R. Long 81 ISCAS 2006 0-7803-9390-2/06/$20.00 ©2006 IEEE