Optical receiver module optical transmitter module phase-locked loop circuit voltage-controlled oscillator and frequency response controllable amplifier
US6501583B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1999 |
| Grant date | Dec 31, 2002 |
| Priority date | — |
| Expiry date | Oct 14, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/033
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Two sets of a high speed differential amplifier and a low speed differential amplifier are prepared, and frequency response speeds of these high speed/low speed differential amplifiers are different from each other. Both an oscillating frequency and a frequency modulation sensitivity of a ring oscillator type voltage-controlled oscillator circuit can be separately set by adding two outputs of these differential amplifiers to each other and by varying the selection ratio of these high speed/low speed differential amplifiers in a linear manner. Thus, the setting ranges for the oscillating frequency and the frequency modulation sensitivity are enlarged. At this time, since a summation of currents flowing through the high speed/low speed differential amplifiers is continuously made constant, the oscillating frequency depending characteristic of the output amplitude of the VCO circuit can be canceled. Furthermore, since control signals are supplied in a differential structure, increasing of jitter components caused by the common mode noise can be suppressed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.