Design of a Wideband Feedforward Distribution Amplifier

The design of a wideband feedforward amplifier in the frequency range 40-300 MHz is described. It is shown that the technology is now available to push the output level over 1 volt for a 12 channel NCTA crossmodulation ratio of -60 dB, or over 1/2 volt for a 35 channel NCTA crossmodulation ratio of -60 dB. The triple beat and second order distortion are typically -80 dB down at the output level of 1 volt. This ultralinear feedforward amplifier is thus an immediate substitute for two distribution amplifiers of conventional design.