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33MHz震蕩電路(有圖)問(wèn)題請(qǐng)教 |
| 作者：emi3721 欄目：技術(shù)交流 |
我的一個(gè)項(xiàng)目用到如圖的33MHZ.html">33MHZ震蕩器.但不知為什么開(kāi)機(jī)時(shí)震蕩頻率老是只有10.8MHz,如果換晶體,則可能變了頻率,但不時(shí)想要的33MHZ.但如果用起子碰一下輸入端13腳,那么震蕩頻率就變了正常的33MHZ.html">33MHZ了. 這是什么原因?請(qǐng)各位大蝦指教.不勝感激! * - 本貼最后修改時(shí)間：2005-4-7 8:41:35 修改者：emi3721
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| 2樓： | >>參與討論 |
| 作者： znh406 于 2005/4/7 9:15:00 發(fā)布：
用該電路產(chǎn)生過(guò)24M的,沒(méi)問(wèn)題. 33M,沒(méi)試過(guò). |
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| 3樓： | >>參與討論 |
| 作者： emi3721 于 2005/4/7 9:28:00 發(fā)布：
多謝回復(fù) 頻率低點(diǎn)是沒(méi)有問(wèn)題.我也試過(guò),但用33MHZ就不行了.這是為什么啊? |
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| 4樓： | >>參與討論 |
| 作者： oldli 于 2005/4/7 12:08:00 發(fā)布：
你用的是33MHZ三次泛音晶體，基波11MHZ。 30MHZ以上基本是泛音晶體，這個(gè)電路只管基波，不好隨便用的。 |
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| 5樓： | >>參與討論 |
| 作者： emi3721 于 2005/4/7 13:06:00 發(fā)布：
oldli好厲害.感謝你了! 請(qǐng)問(wèn)該用什么電路? |
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| 6樓： | >>參與討論 |
| 作者： cqs168 于 2005/4/7 14:18:00 發(fā)布：
采用晶體振蕩再選頻 最好控制在6諧波內(nèi)否則電路復(fù)雜。 |
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| 7樓： | >>參與討論 |
| 作者： yuhengw 于 2005/4/7 14:19:00 發(fā)布：
泛音晶體的緣故,建議使用三點(diǎn)式震蕩電路 |
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| 8樓： | >>參與討論 |
| 作者： emi3721 于 2005/4/7 15:16:00 發(fā)布：
感謝OLDLI, 我放狗的電路,大家看看能否用一個(gè)反相器實(shí)現(xiàn)? Introduction to Fundamental CRYSTAL Oscillators 1 - 21 MHz CRYSTAL UNITS manufactured by Quartslab Marketing Ltd for use over the frequency range 1 to 21 MHz use an AT cut quartz PLATE and operate in their fundamental mode. CRYSTAL UNITS may be specified for operation in either a series or parallel resonant condition. This operating condition should be correctly specified when ordering or the CRYSTAL unit will not operate on the correct frequency. Typically, over the frequency range of 1 - 21 MHz there may be between 2 and 15 kHz difference between the parallel resonant and series resonant conditions, the series resonant condition being lower in frequency. If parallel resonance is required, it is necessary to specify a load capacitance for the CRYSTAL. This capacitance is not related to any capacitance present in the CRYSTALs or the CIRCUIT but refers to the load capacitance used when CRYSTALs are measured in STANDARD TEST sets. The preferred VALUE of capacitance is 30 pF but CRYSTALs can be manufactured for other VALUEs. These CIRCUITs are designed for non-critical adjustment and operation with easily available components. In each case, an OUTPUT of at least 500 millivolts RMS is available across a load of 1000 ohms in parallel with 15 pF. The CIRCUITs are suitable for use with supply voltages from 5 to 10 volts DC. Over this voltage range frequency stabilities of 0.001% (10 ppm) should be achieved. Please note that where no load capacitance is specified for fundamental CRYSTALs we supply them calibrated for a 30 pF load and although the CIRCUIT is shown as suitable for CRYSTALs at 0.95 MHz (950 kHz) we do not offer CRYSTALs below 1.5 MHz. Series Resonant CIRCUIT (see fig1) R1, R2, R3, R4 See Below C1, C2, C3, See Below C4 0.01ΜF C5 47PF TR1 BC108 or similar L1 CLOSE wound with 37SWG enamelled wire on 7.62mm diameter former with Neosid F25 COIL Frequency of X1 MHz R1 R2 R3 R4 C1 C2 C3 L1 0.95 -1.65 68k 33k * 2.2K .0047mf 680 pF 680 pF 140 Turns 1.6 - 2.5 68k 33k * 2.2K .0047mf 680 pF 680 pF 65 Turns 2.5 - 4.0 68k 33k 560 ohm 1.5K .0047mf 220 pF 220 pF 65 Turns 4.0 - 6.0 15k 6.8K 560 ohm 1.5K .001mf 270 pF 270 pF 40 Turns 6.0 - 10.0 15k 6.8K 560 ohm 1.5K 150 pF 220 pF 220 pF 26 Turns 10.0 - 15.0 15k 6.8K 560 ohm 680 ohm 100 pF 220 pF 220 pF 16 Turns 15.0 - 21.0 15k 6.8K 560 ohm 680 ohm 100 pF 100 pF 100 pF 10 Turns
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| 9樓： | >>參與討論 |
| 作者： emi3721 于 2005/4/7 15:20:00 發(fā)布：
并聯(lián)基頻振蕩器 Parallel Resonant CIRCUIT R1 100K R2 33K R3 See below C1, C2, C3 See below C4 . 01ΜF C5 47PF VC 60pF Trimmer TR1 BC108 or similar Frequency of X1 MHz R3 C1 C2 C3 0.95 -3.0 3.3K 220 pF 220 pF not used 3.0 - 6.0 3.3K 150 pF 150 pF 33 pF 6.0 - 10.0 2.2K 150 pF 150 pF 33 pF 10.0 - 18.0 1.2k 100 pF 100 pF not used 10.0 - 18.0 1.2k 100 pF 100 pF not used 18.0 - 21.0 680 ohm 68 pF 33 pF not used
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| 10樓： | >>參與討論 |
| 作者： emi3721 于 2005/4/7 15:23:00 發(fā)布：
三泛音振蕩器 Introduction to Overtone CRYSTAL CIRCUITs With overtone operation of CRYSTALs, the overtone frequency is not an exact multiple of the fundamental frequency and the CIRCUIT design must ensure that the CRYSTAL does in fact operate at the overtone frequency. In order to be certain of correct operation, it is preferable to specify series resonant CRYSTALs, and to provide external CIRCUIT elements to prevent oscillation at the fundamental frequency. Where parallel resonant overtone CRYSTALs are required a load capacitance must be specified On following pages CIRCUITs are shown for 3rd overtone CRYSTALs 15 to 65MHz and 5th overtone CRYSTALs 60 to 105 MHz operating in their series resonant mode. In both of these CIRCUITs with the CRYSTAL SHORT CIRCUITed, the oscillator should operate at or near the required frequency. With the CRYSTAL in CIRCUIT L1 should be adjusted for either (a) MINIMUM voltage across the CRYSTAL or (b) for the exact frequency required. Ideally, these two points would coincide but they rarely will due to the need for a manufacturing tolerance on CRYSTAL frequency. If L1 is of incorrect size it is possible for the oscillator to operate on a different order of overtone, for this reason it is important to accurately check the OUTPUT frequency. Under no circumstances should a tuned CIRCUIT at the CRYSTAL overtone frequency be included in the collector CIRCUIT of TR1 as this configuration will result in oscillation not controlled by the CRYSTAL. However it is possible to include a tuned CIRCUIT at that point which is twice or three times the CRYSTAL frequency. It is then possible to extract from the collector the harmonics of the CRYSTAL frequency. Unless otherwise specified we supply 3rd overtone CRYSTALs between 21 and 60 MHz. 5th overtone between 60 and 126 MHz and 7th between 126 and 175 MHz. -------------------------------------------------------------------------------- Third Overtone Oscillator CIRCUIT R1 10K R2 4.7K R3 470 Ohm R4 560 Ohm TR1 BF180 or similar C1 C2, C3, C4, See Below C5 0.001mF L1 wound is on a 7.62 diameter former with Neosid F29 core Frequency MHz C1 C2 C3 C4 L1 15 - 20 100 pF 100 pF 68 pF 33 pF 12 Turns 30SWG CLOSE Wound 20 - 26 100 pF 100 pF 68 pF 33 pF 8 Turns 30SWG CLOSE Wound 25 - 31 100 pF 68 pF 47 pF 33 pF 8 Turns 30SWG CLOSE Wound 30 - 43 100 pF 68 pF 47 pF 33 pF 6 Turns 30SWG CLOSE Wound 42 - 55 100 pF 68 pF 47 pF 33 pF 5 Turns 30SWG 6 mm LONG 48 - 65 68 pF 33 pF 15 pF 15 pF 5 Turns 30SWG 6 mm LONG --------------------------------------------------------------------------------
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| 11樓： | >>參與討論 |
| 作者： emi3721 于 2005/4/7 15:25:00 發(fā)布：
五泛音振蕩器 Fifth Overtone Oscillator CIRCUIT XL1 Ri L1 50-70 MHz 2.7 K 7 Turns 6mm LONG 60-85 MHz 2.7 K 5 Turns 5mm LONG 80-105 MHz 1.2 K 3 Turns 6mm LONG. R2 470 ohm Cl l2pF R3 330 ohm C2 18PF R4 470 ohm C3 33PF C4 1000 pF VT1 8F180, SE1O1O or similar. L1 Wound with 20 B & S enameiled wire on 7.62 mm diameter former with Neosid F29 Core. Under no circumstances should a tuned CIRCUIT at the CRYSTAL overtone frequency be included in the collector CIRCUIT of VT1, as this configuration will result in oscillation not controlled by the CRYSTAL.
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| 12樓： | >>參與討論 |
| 作者： emi3721 于 2005/4/7 15:29:00 發(fā)布：
高至200MHZ的泛音振蕩器 OVERTONE CRYSTAL OSCILLATOR FOR UP TO 200 MHz Frequency C1 C2 Ic (mA) RE (Ohms) RL (Ohms) Lp (mH) 75 8 pF 100 pF 25 510 470 0.25 120 8 pF 50 pF 25 390 300 0.1 150 5 pF 25 pF 5 1.1k 600 0.08 200 3 pF 20 pF 5 1.1k 600 0.05 The above diagram shows a true series resonant oscillator CIRCUIT suitable for use up to 200 MHz It is recommended that transistors for use in this CIRCUIT have a high DC gain (HFE) and a low base resistance (RBB). Also ensure that the transit frequency is at least ten times that of the oscillator frequency.
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| 13樓： | >>參與討論 |
| 作者： znh406 于 2005/4/8 13:54:00 發(fā)布：
在12腳并上一個(gè)串聯(lián)LC電路到地. LC的諧振頻率剛好等于基波頻率. |
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| 14樓： | >>參與討論 |
| 作者： djc001 于 2005/4/8 15:14:00 發(fā)布：
去買(mǎi)個(gè)基頻是33M的！ 能買(mǎi)到的；問(wèn)題輕松解決；我買(mǎi)過(guò)30M的；33M的難買(mǎi)但是有；去問(wèn)問(wèn)；搞選頻就麻煩了；會(huì)死人的； |
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| 15樓： | >>參與討論 |
| 作者： EMI3721 于 2005/4/8 16:13:00 發(fā)布：
謝謝樓上兩位 我剛試過(guò)znh406的方法,但能搞出55MHZ的,33MHZ就是出不了.我用的是FM收音機(jī)的本振中頻10.7MHZ陷波線(xiàn)圈電容. |
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