| 摘要 |
A method and a circuit for carrying out the method, for determining the momentary frequency of an analog signal s(t) which is variable over time within a given frequency bandwidth .DELTA.f, as an N-bit number in an N-bit coding range. The circuit includes N detector cells which operate in parallel according to the interferometer principle directly in the original frequency range, to produce respective bit values of the momentary frequency according to a digital code, the bit positions of the code having either an odd or an even bit function with respect to the middle of the coding range, depending on the code. Each cell receives from a signal/phase distributor different phases of the analog signal s(t) and with the use of delay elements, comparators and EX-OR and/or EX-NOR gates, depending on whether the cell corresponds to a bit position having an even or an odd bit function, produces an output in accordance with a corresponding equation. In the case of an i-th cell corresponding to the i-th ordered bit position of N, having an an odd bit function, the output squi (t) is given by squi (t) = sgn ¢s(t) - s(t - 2Ti)! ? sgn ¢-js(t - Ti)!, where "sgn" represents the sign function signum, "j" represents a 90- phase shift of the signal, Ti equal to 2i-1? where ? is a common delay increment, and "?" represents 1-bit modulo addition. In the case of a cell corresponding to a bit position having an an even bit function, the output sqgi is given by sqgi (t) = sgn ¢s(t) + s(t -Ti)! ? sgn ¢s(t - Ti/2)! |
