CN102427348B - Clock generator of frequency spectrum expansion - Google Patents
Clock generator of frequency spectrum expansion Download PDFInfo
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- CN102427348B CN102427348B CN201110297147.8A CN201110297147A CN102427348B CN 102427348 B CN102427348 B CN 102427348B CN 201110297147 A CN201110297147 A CN 201110297147A CN 102427348 B CN102427348 B CN 102427348B
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Abstract
The invention relates to a clock generator of frequency spectrum expansion. The clock generator comprises: an adjustable voltage generation circuit, a switch capacitance circuit, an integrator, a sampling hold circuit, a voltage-controlled oscillator, a first frequency divider, a random modulation signal generation circuit and an offset generation circuit. The adjustable voltage generation circuit and the switch capacitance circuit are connected with an input terminal of the integrator respectively. An output terminal of the integrator is connected with the sampling hold circuit. The output terminal of the sampling hold circuit is connected with the voltage-controlled oscillator. The output terminal of the voltage-controlled oscillator is connected with the first frequency divider. The input terminal of the random modulation signal generation circuit is connected with the output terminal of the first frequency divider and the output terminal is connected with the output terminal of the switch capacitance circuit and the voltage-controlled oscillator respectively. The offset generation circuit generates an offset voltage and an offset current needed by the rest parts. In the invention, the random modulation signal generation circuit generates a certain random signal to influence a frequency signal. The frequency spectrum expansion can be realized and electromagnetic interference can be effectively reduced.
Description
Technical field
The present invention relates to a kind of clock generator of anti-electromagnetic interference, relate in particular to the clock generator that a kind of frequency spectrum based on Bicmos technique is expanded.
Background technology
In various electronic systems, clock signal is an indispensable reference signal, and the clock generating from microprocessor is synthetic to the carrier wave in cell phone, and measurement, remote control and automatically the field such as control all have a wide range of applications.But along with the development of sheet internal clock signal generating circuit, and various application system is more and more higher to the requirement of clock signal, and various electromagnetic interference can not be ignored the impact of clock signal generating circuit.In order to prevent electromagnetic interference, can typically apply the processing method such as shielding and filtration, but need sizable cost.By expanding spectrum technology modulation clock signal frequency, so as by concentrate on characteristic frequency energy even be extended on wider frequency band.Utilize this spectrum technology modulation technique, can reduce electromagnetic interference and without utilization, there is shielding and/or the filtering method of higher cost.
Conventionally, improved phase-locked loop (PLL) can be used for generating expansion spectrum clock signal.Yet because PLL circuit is comparatively complicated, especially, for semiconductor integrated circuit design, its power consumption is also larger, so the use of PLL is normally undesirable for expanding spectrum clock signal.
The method that realizes spectrum modulation mainly contains triangular wave and sinusoidal wave and random signal modulation etc. are several.But the shape of modulation signal can affect the shape of disturbance spectrum.Comparatively speaking, random signal modulation improves periodic signal, if the clock source of electronic system is change at random, the amplitude modulation(PAM) that (such as frequency hopping) disturbs is so random.
Summary of the invention
The clock generator that the object of this invention is to provide a kind of anti-electromagnetic interference.
For achieving the above object, the technical solution used in the present invention is:
The clock generator that frequency spectrum is expanded, it comprises that adjustable voltage produces circuit, switched-capacitor circuit, integrator, sampling hold circuit, voltage controlled oscillator, the first frequency divider, Stochastic Modulation signal generating circuit, offset generating circuit;
Described adjustable voltage produces circuit and described switched-capacitor circuit and is connected with two inputs of described integrator respectively, described adjustable voltage produces the voltage that circuit produces the centre frequency of controlling described voltage controlled oscillator, described switched-capacitor circuit produces discontinuous electric current, and described integrator produces sawtooth waveforms output voltage;
The output of described integrator is connected with described sampling hold circuit, and the output of described sampling hold circuit is connected with described voltage controlled oscillator, and described sampling hold circuit provides control signal for described voltage controlled oscillator;
Described voltage controlled oscillator produces and is subject to voltage-controlled frequency signal, and the output of described voltage controlled oscillator is connected with the first described frequency divider, and the first described frequency divider produces fractional frequency signal;
The input of described Stochastic Modulation signal generating circuit is connected with the output of the first described frequency divider, the output of described Stochastic Modulation signal generating circuit is divided into two-way, one tunnel is connected with the output of described switched-capacitor circuit, and another road is connected with described voltage controlled oscillator; Described Stochastic Modulation signal generating circuit produces random signal;
Described offset generating circuit and described adjustable voltage produce circuit, described switched-capacitor circuit, described integrator, described sampling hold circuit, described voltage controlled oscillator, the first described frequency divider, described Stochastic Modulation signal generating circuit is connected and produces described adjustable voltage and produces circuit, described switched-capacitor circuit, described integrator, described sampling hold circuit, described voltage controlled oscillator, the first described frequency divider, bias voltage and bias current that described Stochastic Modulation signal generating circuit is required.
Preferably, the D/A converting circuit that described Stochastic Modulation signal generating circuit comprises the second frequency divider, the random code that is connected with described the second frequency divider produces circuit, be connected with described random code generation circuit, the low-pass filter circuit being connected with described D/A converting circuit;
The input that is input as described Stochastic Modulation signal generating circuit of the second described frequency divider; Described low-pass filter circuit is output as the output of described Stochastic Modulation signal generating circuit.
Because technique scheme is used, the present invention compared with prior art has following advantages: because the present invention adopts Stochastic Modulation signal generating circuit to produce certain random signal, affect frequency signal, can realize frequency spectrum and expand, can effectively reduce electromagnetic interference.
Accompanying drawing explanation
Accompanying drawing 1 is that the circuit of the clock generator of frequency spectrum expansion of the present invention is always schemed.
Accompanying drawing 2 is the circuit diagram of the Stochastic Modulation signal generating circuit of the clock generator expanded of frequency spectrum of the present invention.
In above accompanying drawing: 11, adjustable voltage produces circuit; 12, switched-capacitor circuit; 13, integrator; 14, sampling hold circuit; 15, voltage controlled oscillator; 16, frequency divider; 17, offset generating circuit; 20, Stochastic Modulation signal generating circuit; 21, low pass filter; 22, D/A converting circuit; 23, random code produces circuit; 24, the second frequency divider.
Embodiment
Below in conjunction with embodiment shown in the drawings, the invention will be further described.
Embodiment mono-: shown in accompanying drawing 1.
The clock generator that frequency spectrum is expanded, it comprises that adjustable voltage produces circuit 11, switched-capacitor circuit 12, integrator 13, sampling hold circuit 14, voltage controlled oscillator 15, the first frequency divider 16, Stochastic Modulation signal generating circuit 20, offset generating circuit 17.
Adjustable voltage produces circuit 11 and is connected with two inputs of integrator 13 respectively with switched-capacitor circuit 12.Adjustable voltage produces the voltage that circuit 11 produces the centre frequency of controlling voltage controlled oscillator 15, and simultaneously for switched-capacitor circuit 12 provides suitable terminal voltage in the same way.Switched-capacitor circuit 12 produces discontinuous electric current, and integrator 13 produces sawtooth waveforms output voltage.
The output of integrator 13 is connected with sampling hold circuit 14, and the output of sampling hold circuit 14 is connected with voltage controlled oscillator 15, and sampling hold circuit 14 provides control signal for voltage controlled oscillator 15.Voltage controlled oscillator 15 produces and is subject to voltage-controlled frequency signal, and the output of voltage controlled oscillator 15 is connected with the first frequency divider 16, and the first frequency divider 16 produces fractional frequency signal output.
The input of Stochastic Modulation signal generating circuit 20 is connected with the output of the first frequency divider 16, the output of Stochastic Modulation signal generating circuit 20 is divided into two-way, one tunnel is connected with the output of switched-capacitor circuit 12, and another road is connected with voltage controlled oscillator 15.Stochastic Modulation signal generating circuit 20 produces random signal affects frequency signal.
Shown in accompanying drawing 2, the random code that Stochastic Modulation signal generating circuit comprises the second frequency divider 24, be connected with the second frequency divider 24 produces circuit 23, the D/A converting circuit 22 being connected with random code generation circuit 23, the low-pass filter circuit 21 being connected with D/A converting circuit 22.The input that is input as Stochastic Modulation signal generating circuit 20 of the second frequency divider 24; Low-pass filter circuit 21 is output as the output of Stochastic Modulation signal generating circuit 20.
Above-described embodiment is only explanation technical conceive of the present invention and feature, and its object is to allow person skilled in the art can understand content of the present invention and implement according to this, can not limit the scope of the invention with this.All equivalences that Spirit Essence is done according to the present invention change or modify, within all should being encompassed in protection scope of the present invention.
Claims (2)
1. the clock generator that frequency spectrum is expanded, is characterized in that: it comprises that adjustable voltage produces circuit, switched-capacitor circuit, integrator, sampling hold circuit, voltage controlled oscillator, the first frequency divider, Stochastic Modulation signal generating circuit, offset generating circuit;
Described adjustable voltage produces circuit and described switched-capacitor circuit and is connected with two inputs of described integrator respectively, described adjustable voltage produces the voltage that circuit produces the centre frequency of controlling described voltage controlled oscillator, described switched-capacitor circuit produces discontinuous electric current, and described integrator produces sawtooth waveforms output voltage;
The output of described integrator is connected with described sampling hold circuit, and the output of described sampling hold circuit is connected with described voltage controlled oscillator, and described sampling hold circuit provides control signal for described voltage controlled oscillator;
Described voltage controlled oscillator produces and is subject to voltage-controlled frequency signal, and the output of described voltage controlled oscillator is connected with the first described frequency divider, and the first described frequency divider produces fractional frequency signal;
The input of described Stochastic Modulation signal generating circuit is connected with the output of the first described frequency divider, the output of described Stochastic Modulation signal generating circuit is divided into two-way, one tunnel is connected with the output of described switched-capacitor circuit, and another road is connected with described voltage controlled oscillator; Described Stochastic Modulation signal generating circuit produces random signal;
Described offset generating circuit and described adjustable voltage produce circuit, described switched-capacitor circuit, described integrator, described sampling hold circuit, described voltage controlled oscillator, the first described frequency divider, described Stochastic Modulation signal generating circuit is connected and produces described adjustable voltage and produces circuit, described switched-capacitor circuit, described integrator, described sampling hold circuit, described voltage controlled oscillator, the first described frequency divider, bias voltage and bias current that described Stochastic Modulation signal generating circuit is required.
2. the clock generator that frequency spectrum according to claim 1 is expanded, is characterized in that: described Stochastic Modulation signal generating circuit comprises the low-pass filter circuit that the second frequency divider, the random code being connected with described the second frequency divider produce circuit, the D/A converting circuit being connected with described random code generation circuit, are connected with described D/A converting circuit;
The input that is input as described Stochastic Modulation signal generating circuit of the second described frequency divider; Described low-pass filter circuit is output as the output of described Stochastic Modulation signal generating circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110297147.8A CN102427348B (en) | 2011-09-30 | 2011-09-30 | Clock generator of frequency spectrum expansion |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110297147.8A CN102427348B (en) | 2011-09-30 | 2011-09-30 | Clock generator of frequency spectrum expansion |
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| Publication Number | Publication Date |
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| CN102427348A CN102427348A (en) | 2012-04-25 |
| CN102427348B true CN102427348B (en) | 2014-04-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201110297147.8A Expired - Fee Related CN102427348B (en) | 2011-09-30 | 2011-09-30 | Clock generator of frequency spectrum expansion |
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Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112615622B (en) * | 2020-12-26 | 2023-03-24 | 上海艾为电子技术股份有限公司 | Spread spectrum clock generator and electronic equipment |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101404569A (en) * | 2007-11-23 | 2009-04-08 | 硅谷数模半导体（北京）有限公司 | Apparatus and method for frequency expansion of reference clock signal |
| CN101621348A (en) * | 2009-07-24 | 2010-01-06 | 哈尔滨工业大学深圳研究生院 | OC-CDMA spread spectrum system and OC-CDMA spread spectrum method based on oblique projection |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010506456A (en) * | 2006-09-28 | 2010-02-25 | キーストーン セミコンダクター，インコーポレイテッド | Spread Spectrum Clock Generator Using Reached Lock Loop Technology |
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2011
- 2011-09-30 CN CN201110297147.8A patent/CN102427348B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101404569A (en) * | 2007-11-23 | 2009-04-08 | 硅谷数模半导体（北京）有限公司 | Apparatus and method for frequency expansion of reference clock signal |
| CN101621348A (en) * | 2009-07-24 | 2010-01-06 | 哈尔滨工业大学深圳研究生院 | OC-CDMA spread spectrum system and OC-CDMA spread spectrum method based on oblique projection |
Non-Patent Citations (2)
| Title |
|---|
| F Mihalic, D Kos.Reduced conductive EMI in switched-mode DC–DC power converters without EMI filters: PWM versus randomized PWM.《IEEE TRANSACTIONS ON POWER ELECTRONICS》.2006,第21卷(第6期),1783-1794. |
| Reduced conductive EMI in switched-mode DC–DC power converters without EMI filters: PWM versus randomized PWM;F Mihalic, D Kos;《IEEE TRANSACTIONS ON POWER ELECTRONICS》;20061130;第21卷(第6期);1783-1794 * |
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| CN102427348A (en) | 2012-04-25 |
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