|
| |
Since a crystal unit performs mechanical vibration, too much vibration may lead to unstable oscillation frequency, and finally to destruction in the worst case. When designing an oscillation circuit, the level of drive should be examined so as to use an oscillator below the level specified by TGS. Fig.7 shows an example method of confirming a level of drive. This method employs a current probe to measure the crystal oscillator current. In this case the level of drive is as follows:
|
|
| |
|
|
| |
|
|
Level of drive = Lq2RL RL = [1+(C0 / CL)]2 X R1
Where RL =loaded resonance resistance
R1 = resonance resistance of crystal unit
Lq = current flowing in crystal unit
CL = load capacitance C0 = shunt capacitance
Lq = current flowing in crystal unit
C0 = shunt capacitance
CL = load capacitance
|
|
|
| |
|
|
| |
|
|
| |
|
|
|
|
|
