h a weight function that empha- sizes the characteristic in the 1 MHz passband by a factor of 10 dB. The desired downconversion behavior from fo to baseband, determined by the HTM element ,((s), is dominated by the contribution of 0-th order in . It is given by (4.99) with Vosc being the amplitude of the local oscillator signal and Go,o(s) given by (4.98). At low frequencies, this expression can be approximated as (4.100) It exhibits a lowpass behavior, as was to be expected. Comparison with numerical computations shows the full expression (4.99) to be accurate up to 0.01%. For the HTM elements Ho,o(s) and H0,2(s), things are more complicated. The expres- sion for ,((s) contains 11 terms while the one for H0,2(s) contains 8 terms. In both cases, no term is really dominating. As an example, we list the first couple of terms of 4.3.7 Application 1: linear downconversion mixer the HTM element H0,2(s): (4.101) L(s)L(s+jwo)Yfb(s+jwo) = - , are as defined in (4.98) and the Vn1,k are the Fourier coefficients corresponding to the time-varying operating point Vn1 (t) in equation (4.87). The full expressions for both H0,0(s) and H0,2(s) can be found in appendix C. For purpose of analysis, the terms in the expressions for Ho,o(s) and H0,2(s) can be grouped by combining those having a similar low-frequency behavior. In most cases, this concerns the frequency range of interest. Grouping is accomplished by using the fact that, typically, for s< wo and k#0, the factors of the form H(s+ jkwo) occurring in the terms above can be approximated as H (st jkwo) 22 H (jkwo), i.e. a constant. This leads us, for example, to group the first two terms in expression (4.101), since both are proportional to as their low-frequency behavior is concerned. Combining terms in this way, Ho,o(s) contains 3 components and H0,2 (s) 2. This provides a much better starting point for analyzing and interpreting the expressions. For example, for s w looks like H0,0(s) 22 (4.102) +C3 Yfb(s) BVosc (4.103) with the coefficients C1 (Vosc, wo,...), C2 (Vosc,wo,