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[问答] 8590A具有小漂移和不稳定性
241 连接器
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嗨伙计们,我一直在研究一个有缺陷的8590A。
*症状:*开机时频率约为-700 Khz。
30分钟后,大约+300 Khz。
上电后显示的信号每秒漂移约+ 10 Khz。
30分钟后,这种漂移速度在30秒内减慢到约+ 10Khz。
没有错误代码。
*进行了测试:*当设置为零跨度时,在另一个分析仪上观察到的LO输出也会漂移,这应该使LO正确冻结?
Cal出299.9Mhz是正确和稳定的。
分析仪测试看起来都很好,主线圈DR,FM线圈博士,FM跨度,二进制跨度等...没有抖动和所有级别看起来按照手册。
在YTO连接器附近温和吹风加热A7会影响频率。
YTO由A7,加热器,粗,细和Vcc驱动。
但是服务手册没有提供详细的A7原理图(来自Keysight网站)。
所以也许YTO很好,而A7就是问题......任何人都可以建议下一步吗?
我应该尝试测量YTO的控制和电压线吗?
如果没有A7的扩展卡,很难获得。
提前致谢。
RayEdited:RayP于2015年1月18日上午10:52

以上来自于谷歌翻译


     以下为原文

  Hi folks,
I have  been working on a faulty 8590A.
*Symptoms:*
It is about -700 Khz off frequency at power on.
After 30 min it is about +300 Khz off.
The displayed signal drIFts about + 10 Khz per second after power on.
This rate of drift slows to about +10 Khz in 30 seconds after 30 min on time.
There are No error codes.

*Tests carried out:*
The LO out viewed on another analyser is also drifting when set to zero span which should freeze the LO right ?
The Cal out 299.9Mhz is correct and stable.
Analyser tests all look good, Main Coil DR, FM Coil Dr, FM Span, Binary span etc…
No jitter and all levels look as per manual.

Gentle hairdryer heating of A7 near the YTO connector _instantly_ affects the frequency.
The YTO  is driven from A7, heater, coarse and fine and Vcc.
But the service manual does not provide a detaiLED A7 schematic diagram (from Keysight website).

So perhaps the YTO is fine and A7 is the problem...

Can anyone aDVIse next steps?
Should I try to measure the control and voltage lines to the YTO?
It’s hard to get as without an extender card for A7.

Thanks in advance.

Ray

Edited by: RayP on Jan 18, 2015 10:52 AM  
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2018-11-16 11:00:17   评论 分享淘帖 邀请回答
2个回答
Hi Ray,你需要了解的关于* 8590A *的第一件事是,这个乐器是8590系列乐器中的第一个,它没有锁定的第一个LO,所以它会漂移。
_这些仪器的精度和漂移规格如下:_频率精度:* + / - 5 MHz +频率范围的1%*漂移:*

以上来自于谷歌翻译


     以下为原文

  Hi Ray,

The first thing that you need to understand about the *8590A* is that this instrument was the very first of the 8590 series instruments and it does not have a locked 1st LO in it, so it will drift.

_The specifications for accuracy and drift of these instruments are as follows:_

Frequency Accuracy: *+/- 5 MHz + 1% of frequency span*

Drift: *<50 kHz / 5 minutes after 2 hour warm-up and 5 minutes after setting center frequency*

So, as you can see, the accuracy and drift that you are seeing is well within the advertised performance of this instrument. To get a more accurate and stable 8590 series you would need at the least an 8591A.

You can read more about the specifications of this instrument in Table 1-1 of the Installation and Verification Manual

http://literature.cdn.keysight.com/litweb/pdf/08590-90131.pdf

Best regards,
Mike
2018-11-16 11:15:42 评论

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cmh23 发表于 2018-11-16 15:52
Hi Ray,你需要了解的关于* 8590A *的第一件事是,这个乐器是8590系列乐器中的第一个,它没有锁定的第一个LO,所以它会漂移。
_这些仪器的精度和漂移规格如下:_频率精度:* + / - 5 MHz +频率范围的1%*漂移:*

嗨,迈克,当然你是100%正确的,我今天偶然发现了这个规格的预告片,只是让自己满意,一切都好。
你的电子邮件确认给我;-)我通常使用8563A并愚蠢地期望类似的结果!
关闭有明显的抖动(10 KHz跨度)说+ - 1Khz我想这也是可以接受的。
用户必须习惯单次扫描才能获得稳定的读数。
问候,雷

以上来自于谷歌翻译


     以下为原文

  Hi Mike,
Of course you are 100% correct, I stumbled accross this spec eariler today and just about satisfied myself that all is ok.
Your email confirms it for me ;-)

I normally use an 8563A and foolishly expected similar results!

Close in there is noticable jitter (10 KHz span) say +- 1Khz I guess this is acceptable also.
A user must get used to single sweep for stable readings I guess.

Regards,
Ray
2018-11-16 11:34:51 评论

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