FSK or FM burst signal generating apparatus
AssigneeNEC Corporation
InventorKiyoshi Ohta
Life of this patent
Estimating the term…
Abstract
A burst signal generating apparatus and related method includes a modulator circuit for modulating a carrier wave of an intermediate frequency signal with a modulating signal. The output of the modulator having a carrier wave frequency is converted to a radio frequency which is amplitude controlled in response to a burst control signal. The carrier wave of the intermediate frequency is switched in response to a burst control signal. Thus, a carrier wave of the radio frequency signal has a desired envelope, permitting ready suppression of the carrier wave during pauses between burst signals.
Claims14
A burst signal generating apparatus comprising:
- a modulator circuit for modulating a carrier wave of an intermediate frequency with a modulating signal;
- switching means responsive to a burst control signal for switching on and off the modulated carrier wave of said intermediate frequency;
- a frequency converter circuit for converting the output of said switching means into a radio frequency;
- an amplitude control unit including a prebiassed high-powered amplifier and responsive to said burst control signal for controlling the amplitude of the carrier wave of said radio frequency;
- and
- said amplitude control unit comprising said prebiassed high-power amplifier for power-amplifying the carrier wave of said radio frequency;
- an envelope detector circuit for branching the output of said prebiassed high-power amplifier and detecting the amplitude thereof;
- a comparator circuit for amplitude-comparing said burst control signal and the output of said envelope detector circuit to provide the resultant error signal:
- and a circuit responsive to said error signal for controlling the amplitude of the carrier wave of said radio frequency.
A burst signal generating method comprising the following steps of:
- smoothening the leading and trailing edges of a burst control signal;
- modulating a carrier wave of an intermediate frequency with a modulated signal;
- switching on and off the modulated carrier wave of said intermediate frequency in response to said burst control signal;
- converting the modulated carrier of said intermediate frequency which has been switched on and off into a carrier wave of a radio frequency;
- amplitude-controlling the carrier wave of said radio frequency in response to a smoothened burst control signal by detecting the power amplified output, comparing said burst control signal and the detected output to generate an error signal, and amplitude-controlling said carrier wave of the radio frequency in accordance with said error signal;
- and
- power amplifying the amplitude-controlled output with a prebiassed high-power amplifier.
Dependencies are inferred from the claim text.