A wide-band low-shape-factor amplifier module using an acoustic surface- wave bandpass filter

An amplifier module using a novel surface-wave bandpass filter for a spread spectrum communication receiver has been designed to realize wide-band low-shape-factor requirements. This module with a center frequency of 168 MHz has a midband gain of 6 dB, a 7.1 percent fractional bandwidth (3-dB bandwidth of 12 MHz), and an extremely low-shape factor of 1.32 to 1 (ratio of 3 to 40-dB bandwidth). Excellent agreement is cited between the theoretical frequency and impulse responses of the surface-wave bandpass filter and its measured performance.