Communications: electrical – Digital comparator systems
Patent
1994-09-20
1995-11-28
Wambach, Margaret Rose
Communications: electrical
Digital comparator systems
327 35, 327175, H03K 908, H03K 3017
Patent
active
054711878
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 powering down, of the transmitter and receiver sections to minimize transceiver power consumption.
REFERENCES:
patent: 4449102 (1984-05-01), Frazer et al.
patent: 4516083 (1985-05-01), Turney
patent: 4542531 (1985-09-01), Fukumura
patent: 4703520 (1987-10-01), Rozanski et al.
patent: 4761821 (1988-08-01), MaWhinney et al.
patent: 4873702 (1989-10-01), Chiu
patent: 4903257 (1990-02-01), Takeda et al.
patent: 5230088 (1993-07-01), Kramer, Jr. et al.
patent: 5276913 (1994-01-01), Iee et al.
patent: 5319799 (1994-06-01), Morita
patent: 5327582 (1994-07-01), Wong
patent: 5363402 (1994-11-01), Harmon
National Semiconductor Corporation, "Telecommunications Databook", 1992 Edition, pp. 2-98 thru 2-113.
Shigeki Saito et al., "State-Preserving Intermittently Locked Loop (Spill) Frequency Synthesiser for Portable Radio," IEEE Transactions on Microwave Theory and Techniques, vol. 37, No. 12 (Dec. 1989), pp. 1898-1903.
Hansen Jens
Madsen Benny
Petersen Jens T.
National Semiconductor Corporation
Wambach Margaret Rose
LandOfFree
Data signal comparation with self-adjusting threshold does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Data signal comparation with self-adjusting threshold, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Data signal comparation with self-adjusting threshold will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2016204