Sensor amplification and enhancement apparatus using digital techniques

Sensor amplification and enhancement apparatus for obtaining an amplified enhanced output from a sensor indicative of the position of a movable member comprising:

• complementary reactance means coupled to said member to provide first and second reactances, namely, a first reactance of a given value for a movable postion and a second reactance of a complementary value for said movable position, whereby as one reactance increases in value due to movement, the other reactance decreases by the same given value for said movement,
• an oscillator coupled to said complementary reactance means and including means for selecting said first reactance to control said oscillator in a first mode and said second reactance in a second mode, to provide a first output period during said first mode indicative of the first reactance value and a second output period during said second mode indicative of said second reactance value,
• digital logic means coupled to said oscillator and operative to provide an output indicative of the difference in the duration of said first and second periods during a given timing interval,
• means including a divider coupled to said digital logic means to cause said logic means to provide at an output a signal indicative of the difference of said first and second periods as divided by the sum of said first and second periods with said signal further characterized by having an amplification factor determined according to the division factor of said divider.

Sensor amplification and enhancement apparatus for obtaining an amplified enhanced output from a sensor indicative of the position of a movable member, comprising:

• complementary reactance means coupled to said member to provide a first reactance of a given value for a first movable position of said member and to provide a second reactance of a complementary value for said same position whereby as one reactance increases in value, the other reactance decreases by the same given amount for said movement,
• means coupled to said reactance means to select said first reactance in a first mode and said second reactance in a second mode, an oscillator coupled to said reactance means and operative to provide a first signal of a given period in said first mode according to the value of said first reactance, and a second signal of another period in said second mode according to the value of said second reactance,
• first counting means coupled to said oscillator and operative to provide a count indicative of a given number of pulses during said first mode and of a different number of pulses during said second mode,
• comparison means coupled to said first counting means and operative to provide a first output signal for a predetermined number of pulses during said first mode and a second output signal for a predetermined number of pulses during said second mode,
• up-down counting means coupled to said comparison means and operative to count in a first direction according to said first signal and in a second direction according to said second signal to provide at an output a count indicative of a difference value between said periods,
• logic means including a divider coupled to said up-down counting means responsive to said count for providing an output signal proportional to the difference of said first and second periods as divided by the sum of said first and second periods and having an effective amplification factor according to the division factor of said divider.