:SOURce:POWer[:LEVel][:IMMediate][:AMPLitude]

Description

Gets or sets the sources power level in dBm. The relation between source power level and source voltage can be described as follows.

Figure: Signal Source

Referring to the figure Signal Source above \(V_0\) describes the internal source voltage and \(V_\mathrm{S}\) the voltage at the output connector which depends on the load (e.g. half of \(V_0\) at \(50\Omega\) load). The output power level \(P\) in \(mW\) is always calculated for a \(50\Omega\) system. Therefore the chosen output power level \(P\) defines the internal source voltage \(V_0\).

\[ V_0 = 2\cdot\sqrt{P\cdot 50\Omega} \]

The output power \(P\) in \(mW\) and the output level \(L\) in \(dBm\) can be converted into each other.

\[ P = 10^{\dfrac{L(dBm)}{10}}mW \]
\[ L(dBm) = 10\cdot\log_{10}\left(\frac{P}{1mW} \right)dBm \]

Typical use cases for loads include high impedance (high \(Z\)) and a \(50\Omega\) load. For a desired output rms voltage \(V_{\mathrm{S}}\) the necessary setting for output power level \(L\) in \(dBm\) can be calculated for these cases.

\[ \text{$50\Omega$ load:} \quad L(dBm) = 10\cdot\log_{10}\left(\frac{V_{\mathrm{S}}^2}{1mW \cdot 50\Omega} \right),\quad V_0 = 2 \cdot V_{\mathrm{S}}\\ \]
\[ \text{High impedance $Z$:} \quad L(dBm) = 10\cdot\log_{10}\left(\frac{V_{\mathrm{S}}^2}{4 \cdot 1mW \cdot 50\Omega} \right), \quad V_0 = V_{\mathrm{S}} \]
Syntax Parameter
:SOURce<ch>:POWer[:LEVel][:IMMediate][:AMPLitude] { <numeric> | MINimum | MAXimum }
Parameters accepted format allowed suffixes possible Errors description
<ch> { 1 | empty } none Invalid channel index Currently only one channel is supported. Empty means 1 is used as default.
{ <numeric> | MINimum | MAXimum } Range from Min. power to Max. power none none The sources output level in dBm
Syntax Response
:SOURce<ch>:POWer[:LEVel][:IMMediate][:AMPLitude]? <numeric>
Parameters accepted format description
<ch> { 1 | empty } Currently only one channel is supported. Empty means 1 is used as default.
Response value description
<numeric> The sources output level in dBm

Sample usage

Set the sources output level to 10 dBm.

var visaSession = new TcpipSocket(VISA_RESOURCENAME);
visaSession.RawIO.Write(":CALC:PAR:DEF GainPhase\n");
visaSession.RawIO.Write(":SOUR:POW 10\n");

visaSession.write(':CALC:PAR:DEF GainPhase\n')
visaSession.write(':SOUR:POW 10\n')

:SOURce:POWer

:SOURce:POWer:MODE

:SOURce:POWer:LIST:FREQuency:POINts

:SOURce:POWer:LIST:FREQuency

:SOURce:POWer:LIST:AMPLitude:POINts

:SOURce:POWer:LIST:AMPLitude