Passive components (resistors, capacitors, transformers, inductors, OSCs, crystal oscillators, filters)

Development of VCXO with Fundamental Oscillation Mode up to 700 MHz

Recent increases in communications traffic call for higher-frequency, lower-noise and higher-accuracy clock signals for high-speed optical communications. Conventional high-frequency oscillators generally use a SAW device or frequency multiplication to convert fundamental frequency to higher frequency.
However, frequency multiplication produces phase noise and degrades jitter performance, as the output signal contains frequencies that are integral multiples of the oscillation frequency. Characteristic curves of frequency versus temperature in SAW devices are generally quadratic curves. If stability is required over a wide temperature range, AT cut is desirable, in which frequency-temperature characteristics are represented as cubic curves. Meanwhile, using existing techniques, the maximum available fundamental frequency has been limited to a range of approximately 200 to 300 MHz, since the higher the frequency, the greater the difficulty of making crystal cuts for AT cut resonators.
Using its proprietary quartz-cutting and circuit-design technologies, Daishinku Corporation has developed the DSV753C series of VCXOs. These voltage-controlled crystal oscillators offer the excellent frequency-temperature characteristics of AT-cut resonators, are free from signal quality degradation resulting from frequency multiplication, and provide high-frequency output up to 700 MHz.

<Main applications>
Trunk line communication base stations, optical transmission devices, radio transmitters and receivers, digital video applications and HDTV-related equipment

Passive components (resistors, capacitors, transformers, inductors, OSCs, crystal oscillators, filters)

Development of kHz-range crystal oscillators

Crystal devices of 32.768 kHz are electronic components used as clock sources in many digital devices. DAISHINKU has developed, among other items, four types of kHz-range crystal oscillators that are suited for smart meters and health care supplies (expected to come into wide use) and automotive electronics (demand for which continues to expand). In general, frequency shift of kHz-range crystal resonator against temperature change exhibits a quadratic curve, frequency shift being likely to become bigger against temperature change.

The latest DSK series employs temperature compensation circuits, while DSO221SR (kHz) employs AT-cut crystal resonator whose frequency shift against temperature change exhibits a cubic curve. These products serve as high-precision time bases that are resistant to the external thermal environment. There has also been demand for added features, such as low current consumption and small size and thinness, as various applications are getting more sophisticated and developed for mobile use. To meet these market needs, DAISHINKU developed crystal devices ideal for various applications, by taking advantage of its frequency adjustment expertise regarding temperature-compensated oscillators (TCXO) and high-precision photolithography processing technologies, among others. One result was small/thin kHz-range crystal oscillators featuring high precision and low current consumption.

<Main applications>
High-precision time bases, smart meters, health care supplies, automotive electronics, general electronic equipment etc.