Power and Match

This menu presents the user with functions for Power and Match calculations.

 

Conversions

This section takes any one of the inputs for match and calculates the others and the Mismatch Loss for the mismatch. In the case presented I have input 14dB Return Loss and have checked the voltage measurement type for a scalar analyzer return loss and it calculated that match value in terms of VSWR and rho. The conversion from dB to rho is performed as 20* Log10(V2/V1). Press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

Figure 82 – Match Conversions

Impedance

This section is for taking the complex System Impedance and the Termination or Device Impedance and calculating the Gamma or complex reflection ratio then figure the scalar rho, VSWR, Return Loss and the Mismatch Loss for Gamma. Press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

Figure 83 – Match by Impedance

 

Power Delivered to Load

This section is to calculate the power delivered to the load. The user inputs the Source Return Loss, System Return Loss, Load Return Loss all in dB and the Source Power in dBm. This will then calculate the Power Delivered to the Load. Press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

 

Figure 84 - Power Delivered to Load

Load Match

One method to improve the match into a device is to add some attenuation. This will increase the load match by double the amount of the attenuator. So if we have say a 13dB return loss input match and we wish to improve, we can add a 3dB attenuator to get a 19dB load. A 6dB Attenuator would make that 24dB return loss. Press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

 

Figure 85 – Load Matching

 

Match Sum

The Match Sum screen allow the user to take two mismatches and add them in a manner to get the Max or Worst case match of the two combined in effect. Enter Return Loss #1 and #2 to calculate. Press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

 

Figure 86 – Sum of Matches

Signal Sum

The upper section will convert power in watts to dBm and vice-versa. It can also compute Vpp and Vrms if impedance in Ohms is specified. If dBm or Watts and Impedance is entered it will compute Vpp and Vrms. C The lower section allows the operator to calculate the power sum of two CW signals. Enter the Signal #1 and #2 values and the In Phase and Out of Phase signal power levels will be computed. Press the Calculate to perform the calculation, Clear to clear the fields and reenter or Close to quit the screen.

Figure 87 – Signal Level and Summation

 

Power Spectral Density

Enter any values Integrated Total Power, Bandwidth or Power Spectral Density in dBm/Hz or dBm/MHz. if entering Total Power and some Bandwidth and you desire to compute total power in some other Bandwidth enter the lower bandwidth value and the dBm/Bw will be computer. Press the Calculate to perform the calculation, Clear to clear the fields and reenter or Close to quit the screen.

Figure 88 Power Match Power Spectral Density

Gain/Loss

This screen gives the user the Gain/Loss in dB power to Voltage or power gain in linear units. Enter any one value to compute the others. Press the Calculate to perform the calculation, Clear to clear the fields and reenter or Close to quit the screen.

 

Figure 89 – Power Match – Gain/Loss

 

Power Error

This section is for determining the error for power meter measurements.

 

Match

This function set has two functions. One function is to figure the match conversions. The other is to compute the Upper and Lower Power Range from the measured Power and the Power Error as a percent error. This is a typical specification for Power Meters. In the case shown of 6.43% is for the Overall Power Error for the Anritsu ML2438 Power Meter.

 

The Power Error Section take the Measured Power and the Power Error as percent and calculate the Upper and Lower Power and Power Error in Watts dBm and Erro in dB. Press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

 

The Match section takes any one of the inputs for match and calculates the others and the Mismatch Loss for the mismatch. In the case presented I have input 14dB Return Loss and have checked the voltage measurement type for a scalar analyzer return loss and it calculated that match value in terms of VSWR and rho. The measurement type radio buttons allow the user to determine if the measurement inputs are scalar voltage based or thermister power based measurements. The difference being how the calculation to convert from dB to rho is performed as 10*Log10(Power Ratio)for power based or 20* Log10(Voltage Ratio) for Scalar or Voltage based measurements. This Scalar/Voltage based measurement covers Scalar analyzers, Vector Analyzers, Spectrum Analyzers and Voltage based Power Measurements. Press CalcMatch to compute and display. Clear to reset and reenter value to retry and Close to Quit.

 

Figure 135 – Power Error Match Conversions

 


Match Sum

The Match Sum screen allow the user to take two mismatches and add them in a manner to get the Max or Worst case match of the two combined in effect. Enter Return Loss #1 and #2 to calculate. Press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

 

Figure 136 – Power Error match Sum

 

Attenuation Match

One method to improve the match into a device is to add some attenuation. This will increase the load match by double the amount of the attenuator. So if we have say a 13dB return loss input match and we wish to improve, we can add a 3dB attenuator to get a 19dB load. A 6dB Attenuator would make that 24dB return loss. Press Calculate to compute and display. Clear to reset and reenter value to retry and Close to Quit.

 

Figure 137 – Power Error Attenuator Match Improvement

 

Power Error

This screen is used to determine the error in power measurement that accounts for the Inputs of Source, Load and Detector matches. Select the appropriate Power or Voltage based measurements and “Press Calculate to perform the calculation and get the Upper and Lower Limit of the power measurement and the Total Uncertainty and also as a percent of total power measured. Clear to reset and reenter value to retry and Close to Quit.

Figure 138 – Power Measurement Error

Transmission Error

This screen is used to determine the error in power transmission measurements that account for the Inputs of Source and Detector matches as well as the Device Under Test Input and Output Return Loss in dB and the Forward and Reverse Transmission coefficients in dB. Select the appropriate Power or Voltage based measurements and “Press Calculate to perform the calculation and get the Upper and Lower Limit of the power measurement and the Total Uncertainty. Clear to reset and reenter value to retry and Close to Quit.

Figure 139 – Power Transmission Measurement Error

 

Coupling Error

This screen is used to determine the error in power measurements using a coupler. It accounts for the Inputs of Source, Load and Detector matches as well as the Coupler Input and Output Return Loss in dB and the Coupling and Isolation Transmission coefficients in dB. Select the appropriate Power or Voltage based measurements and “Press Calculate to perform the calculation and get the Upper and Lower Limit of the power measurement and the Total Uncertainty. Clear to reset and reenter value to retry and Close to Quit.

Figure 140 – Power Error Coupler Based Measurements