System for increasing RF power as a constant over a temperature range and employing reduced transmitter current drain during low power output periods
AssigneeCisco Technology, Inc.
InventorsGerald B. Johnson, James Friedmann
Life of this patent
Estimating the term…
Abstract
A system and method for transmitting data communications through air using a radio. The invention allows the user to select from a number of predetermined output transmission powers. When a lower output transmission power is selected the current drain to the associated amplifier is decreased thereby conserving battery power of the radio. In addition, a detector diode circuit combined with an adjustable gain amplifier combine to provide a feedback mechanism whereby the output transmission power of the radio is held substantially constant over a broad range of temperatures.
Claims14
A method for transmitting data communications through air using a radio comprising:
- receiving a data input signal;
- modulating the data input signal;
- performing a direct sequence spread spectrum operation on the data input signal resulting in a spread data input signal;
- converting the spread data input signal to a spread radio frequency data signal;
- amplifying the spread radio frequency data signal with a first amplifier having an adjustable gain control;
- selectively amplifying the radio frequency data signal with a second amplifier having an adjustable bias current control in accordance with a desired transmission output power, wherein selection of a lower transmission power results in a lower current usage by the second amplifier;
- selectively detecting a power signal from at least a portion of the radio frequency data signal and a printed circuit board coupler that couples transmission power to a radio frequency detector diode circuit;
- converting the at least a portion of the radio frequency data signal to an analog error signal by a digital to analog converter;
- amplifying the radio frequency data signal proportionately with the error signal by adjusting the gain control of the first amplifier to achieve a substantially constant output transmission power over a specified temperature range;
- transmitting the radio frequency data signal through by at least one antenna.
An apparatus for transmitting data communications through air using a radio comprising:
- a receive means adapted for receiving an associated data input signal;
- a modulating means adapted for modulating the associated data input signal;
- a spreading means for performing a direct sequence spread spectrum operation on the associated data input signal resulting in a spread data input signal;
- a converting means for converting the spread data input signal to a spread radio frequency data signal;
- an amplifying means for amplifying the spread radio frequency data signal with a first amplifier having an adjustable gain control;
- an amplifying means for amplifying the spread radio frequency data signal with a second amplifier having an adjustable bias current control for selecting a bias current for a desired transmission output power wherein selection of a lower transmission power results in a lower current drain;
- a detecting means for detecting a power signal created from at least a portion of the radio frequency data signal;
- a coupler means for coupling transmission power to a radio frequency detector diode circuit;
- a converting means for converting for converting the at least a portion of the radio frequency data signal to an analog error signal;
- an amplifying means for amplifying the radio frequency data signal proportionately with the error signal by adjusting the gain control of the first amplifier to achieve a substantially constant output transmission power over a selected temperature range;
- and
- a transmission means adapted for transmitting the radio frequency data signal through at least one associated antenna.
Dependencies are inferred from the claim text.