This is a copy of N2PK's website. Paul has decided to delete his website (See N2PK-VNA on message #5, Jan 2020) from ~Feb 2020.

Paul has made availalable a ZIP file of his entire web site, which has been uploaded as is, no changes made except for this preface. <vk3pe>

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This is a plot of the previous filter's passband insertion loss in dB and group delay, also tested by Harold, and plotted by a VNA group delay test program. This plot, at 2 dB per vertical division and 0.5 kHz per horizontal divison, shows that the passband ripple is under 1 dB and the 6 dB bandwidth is 2.9 kHz. The group delay below, being the derivative of phase with respect to frequency, also quantifies the degree of linearity of the filter's phase vs. frequency characteristic in passband, as seen in the above plot. The sharp increases in group delay at the ends of the passband, about 2.7 milliseconds in this case, are characteristic of filters that have been optimized for skirt selectivity. These group delay 'ears' represent a loss in fidelity that can be particularly troublesome in narrow CW and data filters.

Crystal Filter Group Delay


Please feel free to contact me with any comments or questions at: see above

Paul Kiciak, N2PK

Last updated: 19 Oct. 2006
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