New frequency synthesizer locks channel within 20 microseconds

Picking up the remote control and switching among the exciting shows is based on a component of the TV called the "frequency synthesizer." However, people often encounter such distress. The number of channels received is limited, and programs that they want to watch cannot be found. To solve this problem, it is necessary to increase the bandwidth of the frequency synthesizer. Recently, the research team of Associate Professor Tang Changwen of Fudan University achieved a breakthrough in this issue, increasing the ratio between the highest frequency and the lowest frequency generated by the frequency synthesizer from 2 in 2009 to 2.4 today, which is a wider range of frequencies. Fast switching provides the conditions. Relevant results were adopted by the 2013 International Conference on Solid-state Circuits, which is known as "The IC Integrated Olympics."

So, what is the role of the increase in bandwidth in addition to more channel choices? Tang Changwen made such a metaphor, just as the widening of roads on the highway not only brought about an increase in traffic capacity, but also the soaring of the speed. The electronic field shows that people can not only switch among more channels, but also can lock frequencies more quickly. According to reports, this new frequency synthesizer can achieve accurate locking frequency in 20 microseconds, far beyond the traditional technology.

The improvement of this technology is also reflected in the electronic noise reduction. Traditionally, crystal oscillators are used as a reference system to calibrate the frequency generated by the core of a frequency synthesizer, the voltage-controlled oscillator, to achieve noise reduction. However, due to the contrast adjustment of the components of the conventional frequency synthesizer, the two kinds of oscillations are changing, which makes the comparison result nonlinear and the result is not ideal. Therefore, this technology fixes the frequency of the reference crystal oscillator, so that the “zero” effect of electronic noise can be achieved and the output signal can be stabilized.

In addition, small integration is a feature of this technology. The realization of all the above functions depends only on a fingernail-sized chip. Compared to traditional fist-sized electronic components, miniaturization has made it possible for mobile terminals such as mobile phones with wireless communication capabilities. This technology has attracted the attention of many international multinational companies, and some companies have begun to study how to use this technology. Technology is applied to future products.