FM transmitter with a delta-sigma modulator and a phase-locked loop
US8442466B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 2009 |
| Grant date | May 14, 2013 |
| Priority date | — |
| Expiry date | Nov 24, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04H40/45
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A frequency modulation (FM) transmitter implemented with a delta-sigma modulator and a phase-locked loop (PLL) is described. The delta-sigma modulator receives a modulating signal (e.g., an FM stereo multiplex (MPX) signal) and provides a modulator output signal. The PLL performs frequency modulation based on the modulator output signal and provides an FM signal. The FM transmitter may further include a gain/phase compensation unit and a scaling unit. The compensation unit may compensate the modulating signal for the closed-loop response of the PLL. The scaling unit may scale the amplitude of the modulating signal based on a gain to obtain a target frequency deviation for the FM signal. The PLL may operate in a transmit mode or a receive mode, may perform frequency modulation in the transmit mode, and may provide a local oscillator (LO) signal at a fixed frequency in the receive mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.