Frequency synthesizer and frequency synthesis method for converting spurious tone to noise
A frequency synthesizer and frequency synthesis technology, applied in the direction of automatic power control, electrical components, etc., can solve the problems of consuming hardware resources, increasing system complexity and cost, etc.
Active Publication Date: 2012-10-17
NOVATEK MICROELECTRONICS CORP
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Problems solved by technology
In addition, in order to keep the output frequency unchanged, the overall average value of random numbers must be zero, so it is necessary to use a signed number system in circuit design, which increases system complexity and cost
Furthermore, in the high-speed operation mode, a high-speed adder is required to add random numbers, which consumes a lot of hardware resources
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[0023] The present invention proposes a frequency synthesizer and a frequency synthesis method, which convert spurious tones into noise by randomizing carry sequences, thereby reducing or removing the negative effects of spurious tones on the overall system.
[0024] Please refer to Fig. 2A and Fig. 2B. Fig. 2A shows a block diagram of a frequency synthesizer according to a preferred embodiment of the present invention, and Fig. 2B shows the accumulation unit of a frequency synthesizer according to a preferred embodiment of the present invention. schematic diagram. The frequency synthesizer 100 includes an accumulation unit 110 and a clock generator 120 . The accumulation unit 110 includes a fractional accumulator 112 , a buffer unit 114 and an integer accumulator 116 . The fractional accumulator 112 is used for performing an accumulation operation based on a fractional operator r to output a carry sequence CS. The carry sequence CS is a 1-bit data stream, which includes a pl...
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The invention provides a frequency synthesizer and a frequency synthesis method for converting a spurious tone to noise. One of the advantages of a direct frequency synthesis technology (such as flying-adder architecture) is that the technology produces arbitrarily variable frequencies through the concept of time average frequency. At an output end of the frequency synthesized by direct frequency, a period with a single type is replaced by a period with two types. Different from a traditional frequency with the period with a single type, wherein the frequency energy is focused on the design frequency, a frequency based on time average frequency spreads a part of the energy to the spurious tone that may be harmful in some application. The spurious tone is resulted from the periodic carrysequence of a fraction adder in the frequency synthesizer. The invention provides the method and the device to break the periodicity and to convert the spurious tone to wide band noise.
Description
technical field [0001] The present invention relates to a frequency synthesizer and a frequency synthesis method, and in particular to a frequency synthesizer and a frequency synthesis method capable of converting spurious tone into noise. Background technique [0002] A frequency synthesizer can provide an accurate and stable frequency source in a frequency range, which is commonly found in modern electronic devices such as radio receivers, mobile phones, satellite receivers or global positioning systems. Frequency synthesis techniques include direct frequency synthesis and indirect frequency synthesis. Among them, direct frequency synthesis technology includes direct digital pulse rate (direct digital pulse rate) and fast accumulator (flying-adder) architecture, etc., which has the advantages of fast frequency change speed and can generate any variable frequency. However, it is easy to generate Excessive spurs lead to unwanted spurious tones in the spectrum of an output s...
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Login to View More IPC IPC(8): H03L7/18H03L7/099
Inventor 修黎明林明杰
Owner NOVATEK MICROELECTRONICS CORP