Tektronix DMM4020 Digital-Multimeter, DMM, VFD-Multiple segment, 20000 counts CAT II 600 V DMM4020-A1 Ficha De Dados

 

 

 

 

3

 

  

3-19 

A voltage measurement is converted to dBm using the following formula (value is the 

measurement value): 

⎟

⎟
⎠

⎞

⎜

⎜
⎝

⎛

=

.

2

*

1000

log

10

 

The reference impedance can be set to any of 21 reference impedances listed in Table 3-5 

by using the list editor as described in the "Using the List Editor" section later in this 

chapter. 

8000 

Ω

 300 

Ω

 93 

Ω

 

1200 

Ω

 250 

Ω

 75 

Ω

 

1000 

Ω

[1]

 150 

Ω

 50 

Ω

 

900 

Ω

 135 

Ω

 16 

Ω

[2]

 

800 

Ω

 125 

Ω

 8 

Ω

[2]

 

600 

Ω

 124 

Ω

 4 

Ω

[2]

 

500 

Ω

 110 

Ω

 2 

Ω

[2]

 

[1] 

Voltage annunciator lit 

[2] 

Audio power readings possible 

To access the reference impedance list, press Q then press W. The reference 

impedance currently selected is displayed, along with the "db" and "ohm" annunciators. 

Press U or V to scroll to the desired value, then press R to select a reference 

impedance and return the primary display to the measurement function. Press any 

function or modifier button to exit the reference impedance list without selecting a new 

value. 
Setting the dB reference resistance to 16, 8, 4, or 2 ohms allows you to use the Meter to 

calculate audio power. After the reference resistance has been set to 16, 8, 4, or 2 ohms, 

press W twice to select the audio power modifier. Power annunciator will be displayed. 
The following equation is used to make a power calculation (volts is the measurement 

value): 

2

=

 

The Touch Hold function holds the results of your measurements on the display. Touch 

Hold is helpful in difficult or hazardous circumstances when you want to keep your eyes 

fixed on the probes and reading the display only when it is safe or convenient to do so. 

When a new, stable reading is detected, a beep is emitted and the display is automatically 

updated. 
To select the Touch Hold function, press I. H is displayed. In Touch Hold, each 

time you press I, a new reading is displayed. To exit the Touch Hold function, press 

and hold I for 2 seconds.