hknightlife

無Phase Noise meter, 不能認真及準確地測量Phase Noise.

用Spectrum Analyzer只能作粗略評估, 比較適合睇Spur, 而唔係準確測量phase noise.  特別係依個signal generator, phase noise < -130dBc/Hz @ 20kHz offset (typical value for 1000MHz Continuous Wave).  普通Spectrum Analyzer LO既Phase noise都高過佢. 無乜意思了.

雖然有0.01ppm
但有無相位噪聲的分佈圖看看?
rutellor 發表於 2010-7-30 12:24

hknightlife

再睇spec, V band可以最好有 < -140dBc/Hz @ 20kHz 既Phase Noise.

morris

......

hknightlife

That's why I have couple of Rubidium references at home.  The stability and accuracy is more than enough for calibrating the RF equipments in most cases.

But, for the actual use (rather than calibration usage), I prefer OCXO because Rubidium reference is damn heavy and power hungry.  And, you may love Rubidium if you have equipment that keeps power up for months or years, thanks to the 1E-9 per annum aging rate in compared with 1E-7 found in OCXO.

其實可以有個銣鐘做reference都已經流晒口水

之前在華強一舊水買了隻10MHz OCXO (XO5032-005)，雖 ...
morris 發表於 2010-7-30 16:04

morris

......

hknightlife

淘寶有二手洋垃圾賣, 應該係無線基站設備拆出黎, 價錢唔貴, 但部份係有問題, PLL lock唔到, 結果係有大約300ppm跳動(唔係offset, 而係永遠跳動, 正常係5分鐘內lock on).  賣家不退不換.

咁銣鐘要幾錢左右呢？ 我諗就算二手都唔平喎......又怕銣膽壽元將盡，又要換個新膽....... ...
morris 發表於 2010-7-30 16:33

hknightlife

請問師兄你既中古頻率計及遠古訊號源係乜野牌子?
兩部野readings 差多少?  機器有幾多年無Cal過?

我都有部中古頻率計，好似都係9位，用OCXO做基準。另外也有遠古訊號源，都應該係OCXO基準。但係兩部野readings 都唔同，都唔知信邊部好...
morris 發表於 2010-7-30 10:16

A-123

I have HP10544 ocxo 10M ,take out from a HP counter,Hameg counter (ocxo),marconi RF Gen(ocxo),But all of them are different reading,I Think Trimble GPS receiver is a cheap way to cal,Stability>accuracy,GPS 1E-11>Rubidium 1E-10>ocxo 1E-9

morris

......

minki

淘寶有二手洋垃圾賣, 應該係無線基站設備拆出黎, 價錢唔貴, 但部份係有問題, PLL lock唔到, 結果係有大約30 ...
hknightlife 發表於 2010-7-30 17:42

我都買左~
都係中左招