I used it for few months and it works great but now i have a problem with the generator. When I plugged the output of the generator and the input of one of the two channels, after 1 kHz the signal become weak. I tested it with an other oscilloscope and an other generator, the problem come from generator.
I tested the output’s impedance of generator with a multimeter and I didn’t have 50 ohms but around 1k ohms !!!
So when I plugged in the generator to test something, the signal become weak.
[quote]When I plugged the output of the generator and the input of one of the two channels, after 1 kHz the signal become weak.[/quote]Does this mean that the problem occurs only when the frequency is higher than 1kHz?
How weak the signal is on different frequencies (e.g. 100Hz, 1kHz, 10kHz)?
[quote]I tested the output’s impedance of generator with a multimeter and I didn’t have 50 ohms but around 1k ohms !!![/quote]I got about similar result. The multimeter displays 1.3k ohms when connected between the generator output and GND. This is OK.
[quote=“benoit”][color=#BFBFFF]I used it for few months and it works great but now i have a problem with the generator. When I plugged the output of the generator and the input of one of the two channels, after 1 kHz the signal become weak. I tested it with an other oscilloscope and an other generator, the problem come from generator.[/color]
I tested the output’s impedance of generator with a multimeter and I didn’t have 50 ohms but around 1k ohms !!!
[color=#BFBFFF]So when I plugged in the generator to test something, the signal become weak.
Thanks for your help[/color][/quote]
Output impedance cannot be accurately determined with an ohmmeter, except on very simplistic output circuits. This is the output circuit of the PCGU1000, if measured with an ohmmeter the reading will be 10.047kΩ, the sum of the 47Ω series resistor and the 10kΩ link to ground:
To do it properly you need to measure the output voltage with no load, and then with a load of a known value; the output impedance will be:
When I plugged the generator in the input of an equipment under test then the signal of the generator is fell down. I tested it in several frequencies and it’s the same thing (I don’t remember exactly how, but I can make some tests if it’s necessary).
I will try to post the diagram of the response but the signal fell down at 500 Hz like a high cut filter. The results between 10Hz and 10kHz are :
I can’t tested today to calculate the impedance but I think I have to plug a low load around 50 Ohms to have maximum of accuracy, isn’t it ? It is safe for the generator ?
It seems that there at the input of the equipment under test there is 1.3uF capacitive load.
It is normal that the generator voltage drops at higher frequencies in this case.
The load impedance at 10kHz seems to be about 15 ohms.
