摘要 |
The use of three identical delay line circuits enables one of said delay circuits to be connected as a minimum delay reference and a second delay circuit to then be continuously compared to said minimum delay reference delay circuit to provide a code which calibrates the second delay line circuit by indicating and controlling continuously the length of the second delay line circuit to provide an exactly 360-degree phase shift of the reference signal under variable temperatures, pressures and voltages. Then, by maintaining the length of the third identical delay line at said determined 360-degree length, and by being able to select any tap output of the third identical delay line circuit responsive to a command, the third delay line circuit provides an adjustable, feedback calibrated, delay line circuit.
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