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https://designers-guide.org/forum/YaBB.pl Simulators >> System Simulators >> SAW filter insert loss https://designers-guide.org/forum/YaBB.pl?num=1151914240 Message started by cybq on Jul 3rd, 2006, 1:10am |
Title: SAW filter insert loss Post by cybq on Jul 3rd, 2006, 1:10am Hi friends, A problem was found that the insert loss of SAW filter synthesized by ADS is not agreed with the specified value if the input and load impedance are different. Isn't a bug in ADS? There is several dB difference. That is to the insert loss ( measured by the output of SAW filter load divided by the voltage when source and load are direct conected) is agreed with the specified value when in/out impedance are the same. But, when I simulated the S parameters, setting up the Term1 and Term2 are the source and load impedances respectively, I get the result that the S21 is the same as the specified value. Why? Thanks in advance. cybq |
Title: Re: SAW filter insert loss Post by pancho_hideboo on Jul 3rd, 2006, 8:23am Hi. What do you mean by "SAW filter synthesized by ADS" ? You synthesized the equivalent LCR circuits from measured S-parameter of SAW filter ? S-parameters are defined by port impedances. So it is natural that S21 is changed when you use different port impedances from vaules in S-parameter measurement. ADS have following function. stos() Changes the normalizing impedance of a scattering matrix Syntax y = stos(S, zRef, zNew, zy) |
Title: Re: SAW filter insert loss Post by cybq on Jul 3rd, 2006, 6:29pm I have tried to synthesized the SAW filter with LCR, but failed. Because it is not possible to synthesie the SAW high selection characteristics with electronical components, instead of using a SAW (which uses the piezoelectric effect to turn the input signal into vibrations that are turned back into electrical signals in the desired frequency range). |
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