34461A相对dB测量仪表显示-100 dB左右的值

困惑在这里A您是否尝试在直流电压上测量dB？
不要以为我听说过这个，似乎是矛盾的吗？
申请是什么？
我猜-100dB是bg噪音？
acV显然确定罗宾



     以下为原文

  Puzzled here A

Are you trying to measure dB on dc V?

Dont think Ive heard of this, seems contradictory? Whats the application?

I guess -100dB is bg noise?

acV obviously ok

Robin

嗨罗宾，谢谢你的回复，但-6dBm一直是Vac，对Vdc确实没有意义:-)我想测量放大器的-6dB点，所以想要读取@ 1KHz的NULL，并改变
显示频率直到-6dB。
（当我将Vac读取为NULL时，读数为0.0000 :-)我的Fluke 45使用dB函数中的REL函数完成工作。
我想34461A上的NULL必须和Fluke45上的REL做同样的事情，但事实并非如此！
阿诺德



     以下为原文

  Hi Robin,
Thank you for your reply, but -6dBm has always been Vac, has no sense on Vdc indeed :-)
I want to measure the -6dB points of an amplifier, so want to NULL the reading @ 1KHz, and change the frequency until -6dB is shown.
(When I NULL an Vac reading, the reading is 0.0000 :-)

My Fluke 45 does the job well, using the REL function in dB's. 
I suppose NULL on the 34461A has to do the same as REL on a Fluke45, but is doesn't !

Arnold

你好A你在使用“数学”功能吗？
这将带你去Vac上的dBm设置为50Hz的空值使用测量ref val然后sub Vac @ say15kHz会显示说-6dB对我有效Robin



     以下为原文

  Hi A

Are you using the "math" function? That will take you to dBm on Vac
set up the null at say 50Hz using measure ref val
then sub Vac @ say15kHz will show say -6dB

works for me

Robin

嗨罗宾，是的我正在使用数学函数来测量dBm。
当您测量@ 50 Hz时，正如您所说，并减去您测量的值@ 15 Khz，不使用该仪器，是否仍然是-6dB的差异？
例如@ 50 Hz = + 10dBm @ 15 KHz = + 4dBm差6dBm Arnold。



     以下为原文

  Hi Robin,

Yes I am using the math function to measure dBm.
When you measure @ 50 Hz, as you said, and subtract the value you measure @ 15 Khz, 
NOT using the instrument for that, is that still a difference of -6dB? 
eg
@ 50 Hz   = +10dBm
@ 15 KHz =  +4dBm
difference        6dBm

Arnold.