Rational frequency divider
AssigneeSiemens Aktiengesellaschaft
InventorsGerhard Quirmbach, Dirk Schnabel
Life of this patent
Estimating the term…
Abstract
A rational frequency divider for generating an integer frequency from a rational frequency, wherein the rational frequency divider contains a memory for storing first and second divider constants, a selection device for selecting one of the stored divider constants, a first counter which counts in synchronism with the oscillations of the rational frequency, a comparison device which compares the value of the first counter with the selected divider constant, a second counter which is coupled to the selection device and the comparison device and counts a number of predetermined time intervals; and a pulse generating device for corming the integer frequency by generating a pulse in response to a signal of the comparison device.
Claims5
A rational frequency divider for generating an integer frequency from a rational frequency, comprising:
- a memory for storing first and second divider constants;
- a selection device for selecting one of the stored divider constants;
- a first counter which counts in synchronism with oscillations of the rational frequency;
- a second counter which is coupled to the selection device and which counts a number of predetermined time intervals;
- a comparison device which compares a value of the first counter with the selected one of the stored divider constants, the second counter being coupled to the comparison device, and the memory storing at least three first and second divider constants;
- and
- a pulse generating device for forming the integer frequency by generating a pulse in response to a signal of the comparison device.
A method for generating an integer frequency from a rational frequency, the method comprising the steps of:
- a) determining and storing quantities g, z and n in accordance with the relation f g = f 0 g z n
- where fg is the integer frequency, f0 is the rational frequency, g is a first divider constant, z is a divider constant counter, n is the number of time intervals, g, z and n are natural numbers, and the quantity g+1 represents a second divider constant;
- b) initializing both a first counter, which counts in synchronism with oscillations of the rational frequency, and a second counter, which counts the time intervals, to the value 1;
- c) selecting one of the first and the second divider constants;
- d) counting the first counter in synchronism with the oscillations of the rational frequency;
- e) detecting equality of the value of the first counter and of the selected divider constant;
- f) generating a pulse upon detection of the equality of the value of the first counter and of the selected divider constant for forming the integer frequency;
- g) resetting the first counter to the value 1;
- h) incrementing the second counter by 1;
- i) repeating steps c) through h), the first divider constant being selected (n-z) times and the second divider constant being selected z times during a cycle of n time intervals;
- and
- k) resetting the second counter to the value 1 after the second counter has reached the value of n and steps c) through g) have been performed n times.
Dependencies are inferred from the claim text.