Modulators – Frequency modulator – Including stabilization or alternatively distortion – noise...
Patent
1998-06-30
2000-04-11
Pascal, Robert
Modulators
Frequency modulator
Including stabilization or alternatively distortion, noise...
331 17, 331 25, H03C 306
Patent
active
060492570
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present relates to a method and an arrangement for frequency modulation of a high-frequency signal, the high-frequency signal being generated with an oscillator that is regulated by comparison of an actual frequency signal with a variable set frequency signal.
BACKGROUND INFORMATION
In radar technology, in particular with range finders, a time-linear frequency modulation is often needed in the form of up and down ramps. High demands are made of the linearity and symmetry of the ramps.
SUMMARY OF THE INVENTION
An object of the present invention is to create a method and an arrangement for frequency modulation of a high-frequency signal with which a high accuracy is achieved at a low cost.
With the method according to the present invention, this object is achieved by the fact that the actual frequency signal comprises pulses with an average repetition frequency which corresponds to an actual frequency, with each pulse being derived from an edge of the high-frequency signal and its phase angle being determined by a predetermined clock pulse; the set frequency signal comprises pulses with an average repetition frequency corresponding to a set frequency; and the pulses increment or decrement an up/down counter from whose count a control voltage is derived for the oscillator.
Derivation of the edges of the high-frequency signal can be accomplished in various ways with the method according to the present invention. At very high frequencies, such as those occurring with the preferred application of the method according to the present invention, it is advantageous if the high-frequency signal of the oscillator is mixed with a signal of a high-precision reference oscillator before extracting the actual frequency signal, and the actual frequency signal is formed from the resulting mixed product. In an alternative exemplary embodiment of the present invention, means are provided so that the signal originating from or derived from the oscillator is subjected to a frequency division before forming the actual frequency signal.
The method according to the present invention has the advantage that the accuracy achieved using digital circuits, so that adjustment is not needed in production or later. Similarly, no measures are needed for compensation for temperature or aging effects.
The actual frequency signal obtained with the method according to the present invention contains pulses whose interval is subject to fluctuations according to the random phase angle of the clock pulse and of the signal derived from the high-frequency signal. On the average, however, the resulting frequency corresponds to the frequency of the signal derived from the high-frequency signal--i.e., it represents the frequency of the high-frequency signal.
Preferably, a current in a first direction or in a second, opposite direction is supplied to a capacitor in order to derive the control voltage in the method according to the present invention as a function of the sign of the count.
According to a further improvement of the method according to the present invention, a variable number is added to the contents of an accumulator at the given clock rate to derive the set frequency signal, and a pulse of the set frequency signal is output when the most significant bit of the accumulator contents jumps to a predetermined binary value. Here again, a pulse train is generated in which the pulses have different intervals but the frequency corresponds on the average to the set frequency.
In this further development, the slope of the ramps can preferably be determined by storing the variable number to be added in another up/down counter and varying it by incrementing and decrementing the counter as a function of modulation signals supplied.
In the method according to the present invention, for selecting a start frequency, the up/down counter can be set at a starting value which, by repeated addition to the respective accumulator contents, results in an actual frequency signal corresponding to a non-frequency-modulated high-frequ
REFERENCES:
patent: 3989931 (1976-11-01), Phillips
patent: 5184093 (1993-02-01), Itoh et al.
patent: 5216389 (1993-06-01), Carralero et al.
patent: 5379002 (1995-01-01), Jokura
patent: 5757239 (1998-05-01), Gilmore
Choe Henry
Pascal Robert
Robert & Bosch GmbH
LandOfFree
Method and arrangement for frequency modulation of a high-freque does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and arrangement for frequency modulation of a high-freque, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and arrangement for frequency modulation of a high-freque will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1179828