Yumi ken kliagut long dispela askim sapos yumi skelim wanem samting tru wanpela 'spectrum analyzer' i save skelim. Tru tumas, em i yusim 'local oscillator' bilong em yet long "skelim" wantaim signal bilong yu. Olsem na, 'local oscillator' (we OCXO i kolim) i mas klin na stap gut tru.
I. Bilong wanem Ultra-Low Phase Noise em i bikpela samting?
Bikpela samting: Stopim nois bilong instramen long ol i no ken ting em i signal we ol i wok long testim
Simplifim intanel straksa bilong wanpela 'spectrum analyzer':
Kristal Osileta → Lokal Osileta (LO) → Miksing → Spektrum Displei
Sapos 'crystal oscillator' i gat bikpela 'phase noise', ol dispela hevi i save kamap:
1. Wokim wanpela "Nois Skirt" (I bikpela samting tru)
Wanpela bikpela nois floa i kamap long tupela sait bilong wanpela strongpela signal, i luk olsem wanpela "tel" o i go bikpela.
Pe:
Ol wikpela signal i stap klostu ol i haitim stret.
Ol giaman signal, intaferens, na ol 'harmonics' i no inap long luksave long en.
2. Limitesen bilong Dynamic Range
Dynamic range i dipen long nois we i kam aut long strongpela signal na bikpela bilong ol wikpela signal.
>>Bikpela nois bilong 'phase' → strongpela signal i "kontaminetim" ol frikwensi i stap klostu.
>>Em i save apim gut nois floa.
Risalt:Wanpela signal we yu ken lukim pastaim long -90 dBc yu ken lukim tasol i go daun long -70 dBc.
Olgeta skelim i save kisim hevi long wanpela "Blurring Filter"
>>Maski yu putim wanpela gutpela, klinpela signal: Autput i luk olsem i "bikpela" (spektral lain i go bikpela).
>>Toksave:Risal bilong mesamen i stap aninit long instramen yet.
Skelim jat bilong bikpela na liklik nois i stap aninit:
Bikpela Nois (Poor Crystal)
Wanpela kain "nois sket" i kamap klostu long bikpela signal.
Eneji i save go long ol frikwensi we i stap klostu.
Ol wik signal i stap hait insait long nois.
Spektrum i luk olsem "i no klia wantaim."
Risalt:Ol wik signal we i stap klostu i no inap long skelim; 'dynamic range' i no gutpela.
DaunbiloNois bilong Fes(Gutpela-Kwaliti OCXO)
Bikpela signal em i sap na klin.
Nois floa i liklik.
Ol wik signal klostu i stap klia.
Risalt:Ol 'low-level spurs inap long stretim; 'dynamic range' i kamap gutpela tru.
II. Bilong wanem em i bikpela samting (OCXO)?
Bikpela samting: Luksave olsem 'Frequency Reference' i no ken senis
Frekwensi bilong 'crystal oscillator' i olsem "rula" bilong olgeta skelim.
1. Tempereture Drift → Frequency Drift
Long ol standet kristal (aninit long TCXO):
Tempereja i senis → ppm-level drif.
Ol samting i kamap:
Spektral pik i save senis senis long lephan na raithan.
Ol skelim we i no wankain long longpela taim.
2. Impak long ol stretpela mesamen
Ol dispela skelim i dipen long 'stability':
Frekwensi Error
Adjacent Channel Power (ACP)
Modulation Analysis (EVM)
Fes Nois Testing
Sapos 'reference source' i no stap:
Yu no inap luksave long "problem bilong signal" na "problem bilong instramen."
3. Wok bilong OCXO
Ol i save hatim kristal i go long wanpela tempereja we i no senis (olsem, 70 digri).
Dispela i abrusim 'temperature-sensitive region.
Bihain bilong samting:
Stabiliti i kamap gutpela long ppm i go long ppb level.
Bikpela tru sotpela taim stebiliti (liklik 'jitter').
III. Multiplikative Relationship, Not Additive
|
Paramita |
Wok |
As bilong Nogut Pefomens |
|
Low Phase Noise |
Em i makim sapos yu inap long "lukim klia" |
Ol signal i stap hait |
|
Bikpela Stebiliti |
I makim sapos skelim i "stret" |
Ol 'frequency drifts' |
Konklusen:
Lukim klia + Nogat drif=Gutpela skelim
IV. Wanpela-Sentens Sumari long Lukluk bilong Enjinia
Pefomens siling bilong wanpela 'spectrum analyzer' em i gutpela bilong 'local oscillator' bilong en.
Low Phase Noise→ Mekim 'spectrum' i "klia" (larim ol liklik samting i kamap ples klia).
Bikpela Stebiliti (OCXO)→ Mekim 'spectrum' i "gutpela" (i stopim 'drift').
Tupela wantaim i bikpela samting tru. Dispela em i as na ol 'high-end spectrum analyzers i save yusim ol 'ultra-stable, ultra-low phase noise OCXOs.
V. HCI High-Stability, Ultra-Low Phase Noise Products
HCI 25x25mm OCXO long 100MHz i save kamapim 'ultra-low phase noise inap long -168dBc/Hz @ 1kHz.
Test Data:
|
@10Hz (dBc/Hz) |
@100Hz (dBc/Hz) |
@1kHz (dBc/Hz) |
@10kHz (dBc/Hz) |
@100kHz (dBc/Hz) |
|
-112 |
-142 |
-169 |
-182 |
-185 |
Sapos yu nidim ol prodak we i gat bikpela 'stabiliti', 'ultra-low phase noise prodak, plis toktok wantaim HCI sels ripresentativ o teknikel enjinia bilong yu.