Data signal comparation with self-adjusting threshold
US5471187A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 20, 1994 |
| Grant date | Nov 28, 1995 |
| Priority date | — |
| Expiry date | Sep 20, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/56
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A radio frequency (RF) transceiver includes a direct modulation transmitter and single down-conversion receiver for operation in a time-division-duplex (TDD) telecommunications environment. A single RF signal source, in the form of a phase-lock-loop (PLL), is used on a time-shared basis to provide both the carrier signal for the transmitter and the local oscillator (LO) signal for the receiver. In the transmitter, direct modulation is effected by modulating a voltage-controlled oscillator (VCO) in the PLL with a burst of the transmit data while opening the loop and holding the loop feedback tuning voltage constant. In the receiver, a self-adjusting comparator threshold is provided for automatically setting and adjusting a demodulated signal comparison threshold used in retrieving the data and data clock from the demodulated receive signal. The interface between the transmitter and receiver and the host controller provides the control signals needed for the time-sharing of the single RF signal source, the proper programming of the PLL for the different transmitter carrier and receiver LO frequencies, the PLL loop control for the direct modulation of the VCO, and the enablement, or p…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.