System for linearizing sweep of voltage controlled oscillator
US4499435A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1982 |
| Grant date | Feb 12, 1985 |
| Priority date | — |
| Expiry date | Sep 30, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B2200/0092
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Non-linearities in the sweep output of a voltage controlled oscillator are automatically linearized by a scheme that compensates for changes in slope of the variation in frequency with time during a high accuracy calibration mode, prior to placing the VCO into real time operation. During the calibration mode the sweep rate of the VCO is slowed down as the operational frequency range of interest is divided into a prescribed number of subfrequency segments or windows. During each window, an input control code, obtained from a random access memory (RAM) and representative of the intended slope of the VCO frequency sweep (for that window of interest), is applied to a digital-to-analog converter (DAC) whose output is integrated and applied to the voltage control input of the VCO. Since the output of the DAC is integrated, the frequency variation control signal to be applied to the VCO is a slope change control signal, which is incrementally adjusted, as required, during successive sweeps of the VCO, so as to produce a precompensated control voltage that will cause the rate of change of the VCO frequency output to track an intended ramp (linear with time) or other chosen frequency variat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.