| 摘要 |
<p>The invention provides an electronic gage amplifier which converts sinusoidal signals representing measurement data from a gage head into a visual display of measurement data. The measurement signals are received by the amplifier at the input of a mixer (54) where they are combined with a coarse adjustment signal (75). The coarse adjustment signal (75), which is provided by a multiplying digital-to-analog converter (MDAC) (72) which is controlled by microprocessor (40), yields a fine adjustment signal when mixed with the measurement signal. The resulting fine adjustment signal is amplified by a preamplifier (54), translated into a steady-state voltage by a programmable-gain demodulate-and-hold circuit (D/H) (58), and converted to a digital word by an analog to digital converter (ADC) (62). The microprocessor (40) compares the resulting digital word to a known reference word and determines any errors introduced by the afore-mentioned circuitry. The coarse adjustment signal, the fine adjustment signal, and the calculated error signal are then combined to obtain a correct measurement value which is then displayed (70).</p> |
