Selection reference · illustrative scenario
Define the filtering task and position
The filter position determines the signal and interference requirements. State center frequency, passband and stopband targets before comparing crystal, LC or other RF-filter approaches.
Engineering: the complete response
Alongside loss and rejection, review bandwidth definition, ripple, impedance, power and any group-delay requirement. Align matching and fixtures with specified conditions before comparing response curves.
Procurement: provide a requirement mask
If original documentation is incomplete, provide passband and stopband targets, package, temperature and signal-chain conditions. Separate mandatory and negotiable requirements to guide candidate and sample discussions.
Scenario: same center frequency, higher insertion loss
Check source/load impedance, matching and bandwidth definition, then retest with consistent fixtures and calibration. A shared center frequency is not evidence of drop-in interchangeability.
Inquiry & validation checklist
- Passband, stopband and bandwidth definition
- Loss, ripple and group-delay limits
- Impedance, power and matching
- Package, temperature and existing documents
