Discussion in 'Wireless & RF Design' started by Cerkit, Oct 19, 2018.

1. ### Cerkit Thread Starter Senior Member

Jan 4, 2009
286
3
Hi,

I have a receiver with an impedance of 50Ohms. I have calculated the minimum receiver sensitivity to be -10dB.

Is there a way I can express the sensitivity in Volts? Can I convert the dB to power then calculate V = P/(R^2)

Thanks

Apr 5, 2008
19,522
3,977
Hello,

It can not be -10dB.
It is likely -10dBμV.
So the level is 10 dB lower than 1 μV.
The sensitivity will be about 0.3 μV.

Bertus

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3. ### Cerkit Thread Starter Senior Member

Jan 4, 2009
286
3
Hi,

Please help me understand. I have a transmitter of 10watts (40dB) and I need to know what the minimum sensitivity of my receiver needs to be if I have losses of 20dB and need to allow for an additional margin of 30dB. Which is why I got -10dB.

So was trying to convert the sensitivity to a voltage value.

But I still need to get my head round a few things clearly.

Apr 5, 2008
19,522
3,977
Hello,

Decibels are a ratio between powers or voltages.
There must be a reference to calculate the power or voltage.
Read the PDF I gave you.

The power of your transmitter is quite high with the mentioned 10 Watts.
It is quite normal for a communication receiver to have a sensitivity of the 0.3 μV, I mentioned.

Bertus

5. ### John_2016 Member

Nov 23, 2016
55
5

10W are not 40dB, but 40dBmW often the W of dBmW is omitted when for instance working with microwave circuits if all values are small.
Not to be confused with dBmV

John BG

6. ### John_2016 Member

Nov 23, 2016
55
5
it would greatly assist the readers of your question to have the question supported with more details like:

1.- transmitter specs: model, circuit, block diagram, a photo