What is called the spurious frequency effect?[ 08-25 11:56 ]

When the signal level of the spurious frequency is as high as that of the basic frequency, the oscillator will oscillate on the spurious frequency, which is called frequency hopping. The spurious frequency mode is often defined as the resistivity or the suppression ratio regarding the basic frequency. For most oscillators, frequency hopping can be prevented with the resistivity of the basic frequency from 1.5 to 2.0 or the suppression ratio from -6dB to -3dB.

What is the spurious frequency?[ 08-25 11:55 ]

The crystal may have frequency oscillation irrelevant with its fundamental frequency or overtone. These needless frequencies are called spurious frequencies. The spurious frequency effect can be inhibited by changing the wafer size, electrode size or silver content in the crystal production process.

What is the instability?[ 08-25 11:54 ]

The instability of the quartz crystal is the measurement of the frequency change caused by the load capacitance of the wafer. The circuit designer can design a range of operating frequency through changing the load capacitance of the wafer. And the range of operating frequency depends on the crystal instability within the range of specified (changing) load capacitance.

What is the ageing rate of the quartz crystal?[ 08-25 11:53 ]

Ageing means the change of the crystal frequency due to time passing by. Ageing will result in the deviation of the frequency in two different directions. And ageing will cause the overall drift of the frequency of the wafer installed in the oscillator.

What are the AT-Cut and the BT-Cut?[ 08-25 11:52 ]

The behavior of the crystal depends on the preset angle at which the crystal bar is cut into wafers to a great extent. The most popular cutting method is AT-Cut. With the same frequency, the BT-Cut results in thicker cutting than the AT-Cut. Therefore, the cutting of the wafer with higher frequency can be carried out by the BT-Cut.

What will happen to the crystal at a temperature beyond the specified range?[ 08-25 11:51 ]

The operation of the crystal will be impacted at a temperature beyond the specified range. We strongly recommend that such situation should be carefully avoided, otherwise the frequency drift will happen and even the full circuit will have fault in a worse case.

What is the main difference between the frequency tolerance and the frequency stability?[ 08-25 11:50 ]

The frequency stability means the peak deviant between the actual frequency and the reference frequency within the range of operating temperature. The reference frequency is usually the frequency of crystal oscillation at the room temperature. And the frequency stability is usually demonstrated by ppm.

What basic information should you provide when ordering the crystal?[ 08-25 11:48 ]

The basic information usually includes center frequency, cutting type (AT/BT), type, resistance (ESR), frequency tolerance, frequency stability, load capacitance, range of operating temperature, driving power supply, ageing rate, and other relevant parameters.