Abstract: A manufacturing module for an RF feed-forward amplifier subsystem that allows for simple and cost-effective assembly, yet provides separate compartments for the different stages of the subsystem, with low RF leakage between the compartments is disclosed. The manufacturing module comprises a printed circuit board having one or more circuit trace layers, and ground planes covering a substantial portion of the top and bottom surfaces. The printed circuited board also has numerous plated-through holes electrically connecting the top and bottom ground planes. The circuit board is sandwiched between a heatsink having a flat upper surface and a machined enclosure having an outer wall and inner divider walls. The plated-through holes, space less than 1/10 wavelength of module's highest carrier frequency apart, serve to electrically connect the heatsink to the machined enclosure, thus creating separate compartments with low RF leakage.

Abstract: A feed forward amplifier circuit which includes a main amplifier, an error correction circuit producing a message error signal, an error amplifier for producing an amplified message error signal that is then subtracted from the amplified and distorted message signal output of the main amplifier prior to a final output circuit, a negative feedback circuit coupled to the final output circuit responsive to a test signal for compensating and minimizing drift in the operation of the error amplifier, and circuitry associated with the negative feedback circuit for detuning performance of the error correction circuit at the test frequency so as to improve the overall circuit performance across a desired operating frequency band while diminishing its performance at the test signal frequency.

Abstract: A feed forward cancellation amplifier system for amplifying radio frequency telephony signals, including a main amplifier, an error correction circuit producing a message error signal, an error amplifier for producing an amplified message error signal that is then subtracted from the amplified and distorted message signal output of the main amplifier prior to a final output circuit, a negative feedback circuit responsive to a test signal for compensating and minimizing variation or drift in the operation of the error amplifier, the error correction circuit including a vector modulator responsive to modified quadrature vector components of the message error signal for producing a single voltage vector error signal, and the negative feedback circuit including an I & Q network for modifying the quadrature vector components of the error signal in the error correction circuit.The preferred form of the invention utilizes PIN diodes to provide voltage controlled attenuators in the vector modulator.