Frequency Discriminator Using a Simple AD Converter for Interface Systems

In optical communication systems, simple and compact interface to control circuits appropriately from outside chips or modules is strongly expected to be provided. In our previous work, Single-Channel Multi-Port Control system (SCMPC) was shown as one of the simple interface systems. To make SCMPC compact, we propose a frequency discriminator using a simple AD converter for receiver in the system. The proposed receiver can handle high speed operation. We confirm its benefits by performing a post-layout simulation in an 180-nm CMOS process. The results of the simulation show that the discrimination speed was two times faster than that for a conventional circuit and the frequency resolution was improved by about 67%.