Wireless video data transmitters and receivers use various frequency filters to enhance signal quality, reduce interference, and improve performance. Here are the main types of frequency filters used in these systems:

1. Low-Pass Filter (LPF)

• Allows low-frequency signals to pass while blocking high-frequency noise or interference.

• Used to suppress unwanted harmonics and out-of-band noise.

2. High-Pass Filter (HPF)

• Allows high-frequency signals to pass while blocking low-frequency interference.

• Helps eliminate unwanted low-frequency noise, such as power-line interference.

3. Band-Pass Filter (BPF)

• Passes a specific range of frequencies while blocking others.

• Essential for selecting the desired transmission frequency and avoiding adjacent channel interference.

• Example: A COFDM transmitter using 2.4 GHz or 5.8 GHz BPF to isolate its operating band.

4. Band-Stop Filter (Notch Filter)

• Blocks a specific frequency range while allowing others to pass.

• Used to eliminate narrowband interference, such as jamming signals or unwanted frequencies.

5. SAW Filter (Surface Acoustic Wave Filter)

• Provides precise filtering for RF and microwave frequencies.

• Commonly used in high-performance COFDM video transmitters to maintain signal integrity.

6. IF Filter (Intermediate Frequency Filter)

• Used in superheterodyne receivers to filter out unwanted signals at the intermediate frequency stage.

• Improves selectivity and reduces noise in wireless video transmission.

7. Adaptive Digital Filters

• Software-based filters that dynamically adjust to changing interference and signal conditions.

• Used in advanced SDR (Software-Defined Radio) based wireless video transmitters.

Why Are These Filters Important?

• Enhance signal clarity by removing unwanted noise.

• Reduce interference from nearby wireless signals.

• Improve range and stability in FPV, surveillance, and broadcast applications.