Recently due to the expansion of the crystal oscillators applications and fast development of wire and wireless communication systems the determining requirements to the oscillators are essential reducing the noise levels, increasing the frequency, decreasing the warm-up time, power consumption and size at the required frequency stability.
Substantially this problem is solved by using crystal resonators-thermostats (CRT) where the oven contains only a piezoelement placed in the vacuum package. Oscillators based on these CRTs have a smaller size, low consumption power, faster warm-up. Improving the CRTs results in frequency stability and noise levels which are comparable or even better than these of the conventionally designed oscillators.
From 1990 till 2009 three generations of crystal oscillators dissimilar in CRT design and manufacturing techniques have been developed in Omsk Research Institute of Communications and Electronics.
Oscillators based on CRT in glass vacuum cases (“Astra”, “Pion”, “Georgin”) have a frequency range of 8–130 MHz, fre-quency stability 5×10-8, power consumption 0,25 W under the normal conditions, warm-up time from 3 m. to 15 s. The phase noise level is up to
-110 dBc/Hz at 1 Hz offsets and up to – 170 dBc/Hz at 10 kHz and higher offsets.
The oscillator series “Onyx” based on CRT in a glass-and-metal cold-welded package HC-37 is realized in a standard package with the volume of which is 4,8 cm3 and height 12 mm. The unified microcircuit set allows the crystal oscillators with different characteristics and designed for different purposes including 8–130 MHz frequency range, 12 V or 5 V supply voltage, sine wave or CMOS output signal to be realized using one base design. The frequency stability and phase noise characteristics are similar to the characteristics of the previous generator oscillators.
«Topaz» series of oven-controlled crystal oscillators includes three models which have the following characteristics: temperature range from 8 to 50 MHz, frequency stability from 5×108 to 1×106, warm-up time from 15 to 5 s. The oscillators are realized using the same unified design and represent a microminiature oven-controlled assembly consisting of the crystal oscillator, temperature regulator and active oscillator placed in the vacuum package DIP-14. As a result the oscillator volume is reduced up to 2 cm3 and power consumption up to 100 mW with high requirements to the frequency stability.