Amplitude equalizers are lossy bandstop filters. Such filters are intentionally “Q-spoiled” to reduce the midband rejection to 5 to 10db. Thus, the equalizer presents a transfer function opposite in amplitude to that of an amplifier or bandpass filter. The equalizer also maintains a low VSWR over the entire band due to its absorptive characteristic.
Delay equalizers consist of coupled arrays of cavities or resonant networks connected to add delays “bumps” at certain points in a passband while not affecting the amplitude flatness. At low frequencies, the equalizers are bridged-tee LC circuits which are connected in series with the filter to be equalized.
Typical amplitude equalizer specifications are:
- Frequency Range: 8.5-18.5 GHz
- High band edge loss: 2 dB maximum
- Center frequency loss: 18 db type
- Lower band edge loss: 8 db typical
- Loss shape: 1/2 sine, adjustable 1 dB
- VSWR: 2:1