Amplitude Ripple
Understanding Amplitude Ripple
Amplitude ripple quantifies how much the gain or loss of a component varies within its passband. Lower ripple indicates a flatter response, which is critical for wideband systems where consistent signal levels across frequency are required.
| Filter Type | Q Factor | Frequency Range | Size |
|---|---|---|---|
| LC Lumped | 50-200 | DC-3 GHz | Small (PCB) |
| Cavity | 1,000-20,000 | 0.1-40 GHz | Large |
| SAW | 500-2,000 | 0.1-3 GHz | Very small |
| BAW/FBAR | 1,000-3,000 | 0.5-6 GHz | Chip-scale |
In filters, ripple is a design trade-off. Chebyshev filters intentionally allow equiripple in the passband to achieve steeper roll-off, while Butterworth designs prioritize maximally flat response at the expense of transition bandwidth.
Frequently Asked Questions
What causes amplitude ripple?
Impedance mismatches, resonant structures, and multi-path reflections within components create standing waves that produce periodic amplitude variations.
How much ripple is acceptable?
Typical specifications range from 0.1 dB for precision measurement systems to 1-3 dB for general-purpose communications equipment.