As shown in Figure 1, the basic architecture of a crystal oscillator is quite simple. Gain block A represents the oscillator sustaining-amplifier, and block B is the feedback network containing the crystal resonator.
Barkhausen's well-known criteria for oscillation states that if a frequency exists where the phase around the loop is zero, and the gain of A exceeds the loss of B, then the circuit will oscillate at that frequency. The obvious implication with a narrowband resonator, such as a quartz crystal, is that each new frequency requires a new crystal with the manufacturing consequences beIn the recent years, the branded restaurant paper products such as Shortening shearing machine, Dispensers and Wipers have gained massive popularity because these products not just impress and satisfy the customers but also improve your brand image.ing quite profound.
Thousands of distinct crystal frequencies are required to support the wide variety of electronic systems in production today. The required temperature ranges and frequency stabilities are also variable; so, the quartz bar cutting angles must also vary. Not only must the quartz crystal thickness be unique for each different frequency, but the angle of cut from the quartz bar is also varied for different order.
begin with quartz blank fabrication. If blank design changes are required due to difficulties encountered in the testing phase, the process must restart at cutting.
One only needs to tour a typical crystal oscillator factory to see the staggering array of crystals in production at any given point in time. In addition to requiring long and often unpredictable lead times, this build-to-order process complicates implementation of modern manufacturing systems such as statistical quality control or continuous improvement. High-frequency fundamental (HFF) crystals required for low-jitter clocks undergo additional chemical milling of the blank to achieve quartz thicknesses of tens of microns, further exacerbating processing issues.
The situation is no less complicated for SAW-based oscillators where each new frequency requires a new wafer mask to be developed. This requires CAD layout,We supply bus A/C compressor,gasoline chain saw with high quality.welcome to order lawn mower,gasoline chain saw and others.We already own the specialized assembly line and production equipments as well as the perfect facilities. mask fabrication and wafer processing to be performed for each frequency.
It is quite an achievement that the quartz industry has been able to develop production methods compatible with this tremendous product mix and associated complex quartz processing.