| 摘要 |
A method and an apparatus for obtaining digital periodic time function signals, and wherein each time function signal is defined by an instantaneous frequency varying in dependence of time within a characteristic period T equal to the period of a first clock signal, includes a generator for generating a second clock signal, period counters for cyclically counting the periods of the second clock signal, a divider for deriving a third clock signal from the second clock signal, and wherein the third clock signal is a subharmonic of the second clock signal, a memory which has a plurality of storage cells for storing groups of binary numbers characteristic of the time function signals, respectively, an address counter for sequentially calling up and reading out the storage cells with the aid of the third clock signal, a logic circuit for enabling the count of one period counter with a predetermined delay with respect to the time of call-up of each corresponding storage cell, and bistable multivibrators for inverting the digital instantaneous values of one time function signal after predetermined counts of the periods of the second clock signal, in dependence of the binary number read out from the memory, whereby a selected digital periodic time function signal is generated, in dependence of the corresponding group of binary numbers stored in the memory and representing the time values of the edges of the digital time function signal which is generated.
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