Rejection

Rejection

ESTIMATING REJECTION PERFORMANCE

Bandpass Filters - Rejection can be determined at any frequency outside of the 3 dB bandwidth for any design with the following values: Center Frequency (F_c), 3dBc Bandwidth (BW_3dB), and the Number of Sections. Rejection Plot are provides with normalization to the specified 3dBc bandwidths for filters with 3 to 8 sections.

To determine the Rejection (dBc) at a Rejection Frequency:

Normalize your data using the following formula:

Number of Bandwidths = (Rejection Frequency - F_c) / BW_3dB

Select Rejection Plot - Select using the applicable percent BW_3dB.

Note that these rejection plots represent an approximation for the indicated filter topologies at the required bandwidth.

Determine Rejection (dBc) using the Rejection Plot and Number of Bandwidths.

REJECTION PLOTS

Rejection Plot 5-8% BW_3dB(Combline/cavity and ceramic resonator filters )

Rejection Plot 9-12% BW_3dB(All topologies)

Rejection Plot 13-16% BW_3dB (Lumped element and combline/cavity filters)

Rejection Plot 17-20% BW_3dB(Lumped element and combline/cavity filters)