Binary phase shift key modulator with programmable level control
First Claim
1. A BPSK modulator for modulating a binary data signal onto a carrier signal for transmission comprisinga center tap transformer having first and second windings,first and second transistors, each having a collector, an emitter and a base, the first and second transistors connected together in a mirror configuration, the bases of the first and second transistors for receiving the binary data signal, the collectors of the first and second transistors being coupled to the first winding of the center tap transformer, the center tap of the transformer being DC biased, and the second winding providing the BPSK modulated carrier output signal,a third transistor having a collector, an emitter and a base, the collector being coupled to the emitters of the first and second transistors, the base being coupled to the carrier signal, andprogrammable gain control means also coupled to the base of the third transistor for providing step-wise level control of the BPSK modulated carrier output signal.
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Accused Products
Abstract
A BPSK modulator for modulating a data signal onto a carrier signal comprises first and second transistors connected in a mirror configuration and a center tap transformer. The collectors of the first and second transistors are coupled to a first winding of the center tap transformer and the BPSK modulated carrier signal is provided at the output of the transformer. Unmodulated data is input to each of the bases of the first and second transistors. The emitters of the first and second transistors are coupled to the collector of a third transistor whose base receives the carrier signal. A programmable gain control circuit is also coupled to the base of the third transistor for step-wise adjustment of the transmit level of the BPSK modulated carrier signal. In this manner, the transmit output level of the modulator may be adjusted when necessary in the event of changing environmental or other considerations.
124 Citations
11 Claims
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1. A BPSK modulator for modulating a binary data signal onto a carrier signal for transmission comprising
a center tap transformer having first and second windings, first and second transistors, each having a collector, an emitter and a base, the first and second transistors connected together in a mirror configuration, the bases of the first and second transistors for receiving the binary data signal, the collectors of the first and second transistors being coupled to the first winding of the center tap transformer, the center tap of the transformer being DC biased, and the second winding providing the BPSK modulated carrier output signal, a third transistor having a collector, an emitter and a base, the collector being coupled to the emitters of the first and second transistors, the base being coupled to the carrier signal, and programmable gain control means also coupled to the base of the third transistor for providing step-wise level control of the BPSK modulated carrier output signal.
Specification