Digital to analog decoder

Claim 1

A DIGITALLY CONTROLLED POSITION SERVOMECHANISM COMPRISING, IN COMBINATION, A PULSE SOURCE, AT LEAST THREE COUNTERS, EACH OF SAID COUNTERS PROVIDING A PERIODIC OUTPUT SIGNAL AT INTEGRALLY RELATED FREQUENCIES WHICH ARE A SUBMULTIPLE OF THE FREQUENCY OF PULSES SUPPLIED THERETO, MEANS CONNECTING THE PULSES FROM SAID PULSE SOURCE TO THE INPUT TERMINALS OF SAID COUNTERS, A FIRST OF SAID COUNTERS PROVIDING A WAVEFORM OF REFERENCE PHASE, A SECOND OF SAID COUNTERS PROVIDING A COARSE WAVEFORM, AND A THIRD OF SAID COUNTERS PROVIDING A FINE WAVEFORM, MEANS FOR INTERRUPTING THE PULSES FROM SAID PULSE SOURCE TO SAID SECOND AND THIRD COUNTERS, MEANS FOR SETTING A COUNT INTO SAID SECOND AND THIRD COUNTERS WHEN SAID PULSE INTERRUPTING MEANS IS OPERATED, THE MORE SIGNIFICIANT DIGIT OF A DIGITAL COMMAND SIGNAL BEING SET INTO SAID SECOND COUNTER AND THE LESS SIGNIFICANT DIGITS BEING SET INTO SAID THIRD COUNTER, MEANS FOR STARTING PULSE FLOW TO SAID SECOND AND THIRD COUNTERS AT A TIME CORREPONDING TO A PREDETERMINED POINT ON SAID REFERENCE WAVEFORM, SAID DIGITAL COMMAND SIGNAL THEREBY BEING REPRESENTED BY THE PHASE DIFFERENCE OF SAID COARSE AND FINE WAVEFORMS FROM SAID REFERENCE WAVEFORM, A CONTROLLED MEMBER, MEANS MECHANICALLY CONNECTING THE SHAFT OF A FIRST SYNCHRO RESOLVER TO SAID CONTROLLED MEMBER, MEANS MECHANICALLY CONNECTING THE SHAFT OF A SECOND SYNCHRO RESOLVER TO SAID CONTROLLED MEMBER, SAID FIRST SYNCRO RESOLVER BEING CONNECTED FOR COARSE MEASUREMENT OF SAID CONTROLLED MEMBER POSITION, AND SAID SECOND SYNCHRO RESOLVER BEING CONNECTED FOR FINE MEASUREMENT OF SAID CONTROLLED MEMBER POSITION, MEANS CONNECTING SAID REFERENCE WAVEFORM TO EXCITE SAID RESOLVERS, SAID RESOLVERES PROVIDING AN OUTPUT SIGNAL WHOSE PHASE IS A MEASURE OF THE CONTROLLED MEMBER POSITION, A FIRST RELATIVE PHASE MEASURING MEANS, MEANS CONNECTING THE FIRST RESOLVER OUTPUT SIGNAL TO SAID FIRST PHASE MEASURING MEANS, MEANS CONNECTING SAID COARSE WAVEFORM TO SAID FIRST PHASE MEASSURING MEANS, AND FIRST MEANS RESPONSIVE TO THE OUTPUT SIGNAL FROM SAID FIRST PHASE MEASURING MEANS TO POSITIONING SAID CONTROLLED MEMBER TO MINIMIZE THE PHASE DIFFERENCE BETWEEN SAID COARSER WAVEFORM AND SAID FIRST RESOLVER OUTPUT SIGNAL, A SECOND PHASE MEASURING MEANS, MEANS CONNECTING SAID SECOND RESOLVER OUTPUT SIGNAL AS ONE INPUT SIGNAL TO SAID SECOND PHASE MEASURING MEANS, MEANS CONNECTING SAID FINE WAVEFORM AS ANOTHER INPUT SIGNAL TO SAID SECOND PHASE MEASURING MEANS, AND SECOND MEANS FOR POSITIONING SAID CONTROLLED MEMBER TO MINIMIZE THE PHASE DIFFERENCE BETWEEN SAID FINE WAVEFORM AND SAID SECOND RESOLVER OUTPUT SIGNAL.