1. Screening: The crystal used is not suitable for the filter (resonant frequency, body quality detection, 25% can be used). 2. Pairing: Crystals must be paired to achieve the best results (only 30% of batches can be paired successfully). 3. Design: Crystal filter circuit design (the input impedance of the crystal changes greatly, matching circuit design). 4. Commissioning: Each crystal has different characteristics. It must be accurately debugged according to the impedance characteristics. 5. Instrument: The crystal filter bandwidth is extremely narrow, and special instruments are needed. Generally, the oscilloscope and spectrum analyzer cannot be used.
Technical Parameters:
1. Operating frequency: 10.7MHz ±7KHz
2. Overall dimensions: 24×47mm (without joints)
3. Out-of-band suppression: >80dB (BW<200kHz)
>60dB (BW<11KHz)
4. Connector form: SMA-KE (shape hole can be customized)
5. In-band fluctuation: <2.5dB
6. System impedance: 50 ohms
7. Insertion loss: 3.5dB (typical)
Precautions
1. Input, output direction port is 50 ohms, only suitable for 50 ohm system
2. The components are precisely matched and require professional equipment to be debugged
3. Any modification may damage the filter
4. The crystal is a precision device and it is strictly prohibited to bump, vibrate, overheat, cold, and warm.
5 each filter is artificial precision debugging, slightly different, do not like to shoot
Filter test chart 
