Frequency synthesizer for a level measuring device and a level measuring device
First Claim
1. Frequency synthesizer for a time base generator of a level measuring device which works according to the radar principle, comprising:
- a reference oscillator for producing a reference frequency signal,a direct digital synthesizer,at least one first output, andat least one second output,wherein the reference oscillator is arranged to interact with the direct digital synthesizer to produce at least one first frequency signal at the at least one first output,wherein the reference oscillator is arranged to produce a second frequency signal at said at least one second output without interconnection of the direct digital synthesizer, the second frequency signal being only slightly different from the first frequency signal,wherein the direct digital synthesizer is adapted to produce only an at least partially minimized noise spectrum, andwherein the direct digital synthesizer is adapted to operate with phase shifts which do not produce noise lines as a result of phase truncation.
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Abstract
A frequency synthesizer for a time base generator of a level measuring device which works according to the radar principle, with at least one first output for output of a first frequency signal, with at least one second output for output of a second frequency signal, and with a reference oscillator for producing a reference frequency signal, the first frequency signal and the second frequency signal having a small difference frequency relative to one another, the first frequency signal being producible by interaction of the reference oscillator with a direct digital synthesizer. The first frequency signal and second frequency signal can be generated with especially low noise by the second frequency signal being derived from the reference oscillator without interconnection of a direct digital synthesizer and the direct digital synthesizer being operated such that only a noise spectrum is produced which is at least partially minimized.
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Citations
15 Claims
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1. Frequency synthesizer for a time base generator of a level measuring device which works according to the radar principle, comprising:
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a reference oscillator for producing a reference frequency signal, a direct digital synthesizer, at least one first output, and at least one second output, wherein the reference oscillator is arranged to interact with the direct digital synthesizer to produce at least one first frequency signal at the at least one first output, wherein the reference oscillator is arranged to produce a second frequency signal at said at least one second output without interconnection of the direct digital synthesizer, the second frequency signal being only slightly different from the first frequency signal, wherein the direct digital synthesizer is adapted to produce only an at least partially minimized noise spectrum, and wherein the direct digital synthesizer is adapted to operate with phase shifts which do not produce noise lines as a result of phase truncation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13)
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10. Frequency synthesizer for a time base generator of a level measuring device which works according to the radar principle, comprising:
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a reference oscillator for producing a reference frequency signal, a direct digital synthesizer, at least one first output, at least one second output, and a first filter between the output of the direct digital synthesizer and a first output of the frequency synthesizer, the first filter being a bandpass filter, wherein the reference oscillator is arranged to interact with the direct digital synthesizer to produce at least one first frequency signal at the at least one first output, wherein the reference oscillator is arranged to produce a second frequency signal at said at least one second output without interconnection of the direct digital synthesizer, the second frequency signal being only slightly different from the first frequency signal, wherein the direct digital synthesizer is adapted to operate with phase shifts, the only resulting truncations of which that produce noise lines are those which produce noise lines that are in a blocking region of the bandpass filter and wherein the bandpass filter is connected downstream of the direct digital synthesizer.
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14. Level measurement device which operates according to the radar principle, comprising:
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a reference oscillator for producing a reference frequency signal, a direct digital synthesizer, at least one first output, and at least one second output, wherein the reference oscillator is arranged to interact with the direct digital synthesizer to produce at least one sampling frequency signal at the at least one first output, wherein the reference oscillator is arranged to produce a transmission frequency signal at said at least one second output without interconnection of the direct digital synthesizer, the transmission frequency signal being only slightly different from the sampling frequency signal, wherein the direct digital synthesizer is adapted to produce only an at least partially minimized noise spectrum, and wherein the direct digital synthesizer is adapted to operate with phase shifts which do not produce noise lines as a result of phase truncation. - View Dependent Claims (15)
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Specification