Previously there was questions about dBm level settings and mostly I can see only then 50ohm impedance in images and in messages.
SDG1000X series (as also what ever brand and model) can not tell dBm for undefined Hi-Z load. Why - may some noob ask. Because dBm is POWER unit. How can set power if load is unknown (high-z).
So with this Hi-Z output setting dBm is disabled. With all other output load settings dBm can use.
With defined loads, power level can set as dBm.
User can define load from 50ohm up to 100kohm.
Example if output freq is over 10MHz Hi-Z max Vpeak-peak is 10V (or 5Vpeak what is same) and internal source impedance is always 50ohm.
Now with 50ohm load this maximum Voltage is of course half, 5Vpeak-peak (2.5Vpeak) and this is 1.77 Vrms and to this 50 ohm load it give 62.5mW what is 17.96 dBm (all values bit rounded)
But then what happend if I set load impedance to some other value.
Say example to 600ohm.
This same maximum output level is now 12.49dBm.
With same setting, maximum level to 100kohm.
Now it give only -9.03dBm
Yes it calculate right value for this load what user have told to generator.
Of course it can also manually calculate if want. Only what need think is this
GND -- [(G~ Ri 0ohm) -- (internal 50ohm) ---(SDGChxOut)] ---
Rload -- GND
And G~ V is same what it tell for Hi-Z V level.
First calculate voltage across this Rload.
Using this voltage calculate power across Rload.
For dBm calculus this AnalogDevices tool is quite good.
http://www.analog.com/en/design-center/interactive-design-tools/dbconvert.htmlNo need calculate (exept that calculations are fun and for young peoples also useful for better understanding things),
of course Siglent SDG´s do it for you.
In this example image
SDG1kX output is set for maximum level using dBm scale and load impedance 600 ohm
Commonly dBm is used for 50ohm system but there is lot of other impedances what we use in practice.
Also SDG2000X series load can set from 50ohm to 100kohm, just same.
Advantage over SDG2000X in SDG1000X is its new square/rectangle wave circuit. It can do full BW Square. (30MHz model 30MHz and 60MHz model 60MHz).
In this image example about SDG1kX 60MHz square. Measured using old HP boat anchor but this scope have real 50ohm input impedance instead of what can find in cheap machines as "50 ohm input".
Also in somewhere in web I have seen some total crap claims that SDG1000X flatness is not very good.
This is what I can see and also I have checked it using HP power meter and results are inline.
Sweep from 5MHz to 60MHz with 4 different levels. (yes, under 1.001Vpeak-peak level flatness is not very perfect but, still quite good.
Edit Add: SA horizontal scale linear. SDG1000X frequency sweep linear.
ETA:
Because some user have asked.
When you go to set Output Load
(Utility >> Output Setup >> Load >> you can here select HighZ or 50ohm. )
If you select 50ohm then you see cursor also apperas over 50ohm. Now you can adjust also other values 50 - 100kohm using adjusting knob or enter value using keyboard)
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