Match Measurement; Equations; Vswr; Return Loss - BIRD BirdTechnologies SignalHawk SH-36S Operating Instructions Manual

Match Measurement

This measurement displays how well matched a system is to a 50 ohm character-
istic impedance. Return loss is a measure of impedance mismatch between two
or more circuits.
The SignalHawk can calculate the system match as VSWR, Return Loss, Reflec-
tion Coefficient, Match Efficiency % and Reflection %.

Equations

VSWR


VSWR = 1 + Sqrt Pr Pf

Return Loss


RL = – 20 log

Reflection Coefficient

1 VSWR –

=
-------------------------
1 + VSWR

Match efficiency %

MatchEfficiency Percent

Reflection %

  
100 1 Pr Pf –
1. Measure the output power of the system being tested, or signal power, at
the system's test port using a power meter, service monitor, or equivalent.
Note: Ensure the output power is less than +22 dBm (160 mW).
2. Power up the SignalHawk.
3. In the Start Menu, use the arrow keys to highlight the desired measure-
ment and press Enter.
4. In the Freq & Span Menu, set the frequency range. See "Freq & Span Menu"
on page 58.
5. Select either Match or Cable Loss measurement.
6. Press Calibrate and press Open, Short, and Load (soft keys) on RF Out with
calibrated open, short, and load on RF Out port.
7. Connect the cable and antenna to the RF Out test port.
Note: Maximum input is +22 dBm (160 mW).
42
     
1 Sqrt Pr Pf –
 
= 100

   
     
1 – Pr Pf