A 2 kHz–100 MHz dynamic amplifier for tracking targets of variable amplitude

A 2 kHz–100 MHz constant-output dynamic amplifier design is presented. Application of the amplifier is shown for tracking wireless magnetoelastic and magnetoacoustic environmental sensors [C. A. Grimes et al., Rev. Sci. Instrum. 70, 4711 (1999); K. Loiselle and C. A. Grimes, Rev. Sci. Instrum. 71, 1141 (2000)], the detected amplitude which varies significantly with spatial location from the detector. The amplification of the dynamic amplifier, 80 dB, is controlled by inverted feedback voltage; the design is suitable for an input voltage range of −150 to −10 dB. The dynamic amplifier enhances the detection range of magnetoacoustic sensors by an approximate factor of three, and that of magnetoelastic sensors by a factor of 1.25, with the magnetoelastic sensors having comparatively less detection range increase due to higher background noise levels.