Self-calibrating variable range phase meter

Claim 1

IN A PHASE ANGLE MEASURING SYSTEM HAVING A METER FOR PROVIDING A VISUAL INDICATION OF PHASE ANGLE, MEANS FOR PRODUCING AN ANALOG SIGNAL VOLTAGE PROPORTIONAL TO PHASE ANGLE, MEANS FOR COUPLIING SAID ANALOG SIGNAL VOLTAGE TO SAID METER WHEREBY TO CAUSE UPSCALE DEFLECTION OF SAID METER, THE IMPROVEMENT COMPRISING AN ADJUSTABLE SOURCE OF D.C. VOLTAGE, A VOLTAGE DIVIDER NETWORK CONNECTED ACROSS SAID VOLTAGE SOURCE, SAID NETWORK HAVING A PLURALITY OF OUTPUT TAPS PROVIDING A PLURALITY OF SUCCESSIVELY SMALLER OUTPUT VOLTAGES WHICH DIFFER IN MAGNITUDE BY EQUAL INCREMENTS, MEANS FOR SELECTIVELY APPLYING A VOLTAGE EQUAL TO THE VOLTAGE BETWEEN TAPS TO SAID METER SO AS TO CAUSE UPSCALE DEFLECTION OF SAID METER, SWITCH MEANS FOR SELECTIVELY CONNECTING EACH TAP TO SAID METER WHEREBY THE OUTPUT AT EACH TAP WILL CAUSE DOWNSCALE DEFLECTION OF SAID METER, SAID VOLTAGE SOURCE ADJUSTABLE TO PROVIDE FULL SCALE DEFLECTION OF SAID METER WHEN SIMULTANEOUSLY (1) SAID VOLTAGE EQUAL TO THE VOLTAGE BETWEEN TAPS IS APPLIED TO SAID METER SO AS TO PRODUCE UPSCALE DEFLECTION OF SAID METER AND (2) SAID ANALOG SIGNAL VOLTAGE IS ZERO, AND MEANS FOR ZEROING SAID METER WHEN SIMULTANEOUSLY (1) SAID ANALOG SIGNAL VOLTAGE IS AT A MAXIMUM LEVEL AND (2) THE TOTAL VOLTAGE ACROSS SAID NETWORK IS CONNECTED TO SAID METER IN OPPOSITION TO SAID ANALOG SIGNAL VOLTAGE.