Bird Technologies SH-362S-Manual - Manual (Page 93)

71
Preamp
Controls the built-in amplifier on the signal input. This lowers the noise floor,
allowing very low power signals be detected, by giving a 24 dB nominal gain boost.
Note: Attenuation is automatically disabled to 0 when Preamp is
activated.
Note: The preamp should not be used with input signals greater than
-30 dBm.
Offset
Shifts the signal to compensate for external factors (attenuation, couplers,
amplifiers, etc.). This allows for a true signal level reading.
1.
Measure the total amount of loss for all attached signal devices.
2. Enter the measured amount as the Offset value or gain.
Example - The system has 10 dB of loss due the use of a coupler;
enter the value of 10 in the Offset. Offset range is -100 to +100.
Units
Sets the units to be displayed on the graph.
dBm
dBuV
dBmV
dBV
Volts
Note: Selecting this unit will disable the Scale option. See “Scale” on
page 70.
Watts
Note: Selecting this unit will disable the Scale option. See “Scale” on
page 70.
dBm 10 Log Power Watts
    30dB
+

=
dBm dBuV 10 50 log
  90
– – =
dBm dBmV 10 50 log 30 –
 
– =
dBm dBV 10 50 log 30 +
 
– =
dBm 20 Log Power Volts
    
= 30dB +
Watts 10 dBm 30 –
  10   
=