AUTOMATIC GAIN RANGING AMPLIFIER

Abstract

The increasing complexity of Air Force aircraft and systems has created a demand for the collection of greater amounts of more accurate, higher dynamic range test data to solve dynamics related problems. The problems presented by higher volume can be resolved by making use of a time sharing Pulse Coded Modulation formatting technique. To meet demands for high dynamic range, the need is apparent for a device which “siphons” the wide dynamic range test data to a range which is compatible with the recording device. The Automatic Gain Ranging Amplifier performs this task and that of increasing the system’s signal to noise ratio. The AGRA has seven gain options from -12 dB to 60 dB (-12 dB is a one step 12 dB attenuation) in 12 dB steps. Gain is controlled by an internal peak detector or by an external (CMOS compatible) processor. Following the amplifier is a four rolloff frequency, six pole Butterworth low pass filter. The AGRA senses the output measurement and automatically adjusts the gain to be within the required recording levels. In this manner, a large number of measurement devices (thermocouples, strain gauges, etc.) whose output swings vary over a large range can be made compatible with a single recording device.