Difference between revisions of "RF Band Pass Filters"
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A band pass filter (LPF) is used at the front end of a receiver, to attenuate strong out-of-band signals. | A band pass filter (LPF) is used at the front end of a receiver, to attenuate strong out-of-band signals. | ||
Strong signals that reach the receiver’s first mixer and/or RF pre-amplifier cross-modulate and produce | Strong signals that reach the receiver’s first mixer and/or RF pre-amplifier cross-modulate and produce | ||
| − | unwanted spurious responses at the receiver output | + | unwanted spurious responses at the receiver output. |
== Design Details == | == Design Details == | ||
Revision as of 12:22, 28 September 2021
A band pass filter (LPF) is used at the front end of a receiver, to attenuate strong out-of-band signals. Strong signals that reach the receiver’s first mixer and/or RF pre-amplifier cross-modulate and produce unwanted spurious responses at the receiver output.
Design Details
- Double-tuned circuit filter
- Based on The double-tuned Circuit: An experimenter's tutorial
- QRP Labs design - Commercially available at reasonable cost
Schematic
Parts
Performance (QRP Labs)
- 20 MHz
- 40 MHz
