Modulator producing phase modulation by combining amplitude modulated signals
US4870374A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 13, 1988 |
| Grant date | Sep 26, 1989 |
| Priority date | — |
| Expiry date | Apr 13, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03C3/40
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A system is described for using the modulation of the phase of a RF carrier as means of transmitting information. The RF input is split into four quadrature components each of which is passed through individual amplitude control attenuators and then summed in a combiner to create the required phase-controlled RF signal. The resultant signal is then amplified in an RF signal amplifier chain as required to achieve the desired output level. The RF output level is sampled and routed back to an in-phase splitter the output of which is compared to the corresponding individual quadrature components of the unmodulated RF signal to generate a signal which is compared with a processor generated modulation reference signal in a control loop amplifier and the resulting error signal is applied to the individual attenuators to adjust the output amplitude of each quadrature component. The quadrature components are then combined to obtain the desired phase-modulated RF output signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.