Phase-shift modulation of a direct antenna-driving VCO
US5966055A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 14, 1997 |
| Grant date | Oct 12, 1999 |
| Priority date | — |
| Expiry date | Feb 14, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03C3/0975
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Apparatus for generating the family of PSK (phase shift keyed) modulations, which include BPSK (binary PSK), QPSK (quaternary PSK), MSK (minimum shift keying) and the like. The carrier is generated with the desired digital information already phase-modulated onto it by directly introducing a phase shift or delay onto the error path of a phase-locked loop. causing the phase-locked loop to create the phase modulation. The [proposed scheme differs from common practice approaches, which are usually implemented by linear synthesis (an AM technique); rather, it] invention employs direct nonlinear synthesis (an FM technique). The invention [yields good phase precision with arbitrary spectral shaping under the constraint of constant envelope signaling. It] permits the connection of the output of a simple, inexpensive VCO (voltage controlled oscillator) directly to a system's antenna without the need for intervening circuit elements such as phase splitters, mixers, and the like which is applicable to [. The resulting minimal implementation will lend itself well to] the power, size and cost constraints of a microminiature radio transmitter as might be required, for example, for the up-link o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.