1. provide the basic clock signal for the system. Usually a system uses one crystal oscillator to keep all parts of the system synchronized. Some communication systems have different fundamental frequencies and radio frequencies using different crystal oscillators, and maintain synchronization by electronically adjusting the frequency.
2. crystal oscillator is used in conjunction with the phase-locked loop circuit to provide the system required clock frequency. If different subsystems require clock signals of different frequencies, different phase-locked loops connected to the same crystal oscillator can be used to provide them.
Standard Environmental Condition:
Environmental Temperature:15℃~35℃
Humidity:45%~85%
Atmospheric pressure:86~106KPa
Operating Temperature Range:-20℃~70℃
Crystal Frequency & Resistance will be tested under the following conditions,
Unless extra requirments:
standard temperature(25±2℃) after heat balance.
Storage Temperature Range:-40℃~+85℃
Mechanical test:
The quartz crystal unit shall be subjected to normal atmospheric conditions for 1hr before being tested.
Dropping Test:
The Units are measured for its frequency and resistance in accordance with Table1 & without mechanical damage,after allowing the crystal to fall freely.
From 75 cm of height 3 times on the firmed wood.
Vibration Test:
The Units are measured for its frequency and resistance in accordance with Table 1&without mechanical damage afer subjectiong to 2hrs of vibration with 0.75mm amplitude with 10~55Hz frequency sweep 20 times.
Sealing Tightness:
Find Lead Test:≤1×10-8atm·cc/S by Helium mass-mass-spectrometer detector,and vacuum and reach 1×10-3Pa；
Resistance to Soldering Heat:
The Units are measured for its frequency and resistance in accordance with Table 1 after dipping into molten solder with the temperature of 320℃±10℃；For 3~4 secs and at a depth up to a point 2.0mm from the base root.
