RF Signals

RF (short for Radio Frequency) signals are sinusoidal waves with frequencies in the MHz and GHz range. While there are RF sources designed specifically for these frequencies, our good friend the Rigol Function Generator can produce frequencies in the lower end of the RF spectrum and should be sufficient for investigating RF signals.

For this module, you will need

• Rigol DG1022 Function Generator
• Rigol DS1102E Oscilloscope
• Micro-circuits ZAD-1 RF mixer
• A selection of BNC cables
• Thorlabs Variable Resistance Terminator

Measuring RF Power

The 8482B power sensor can handle frequencies between 100kHz and 4.2GHz, with powers of 1mW to 25W. The 8481A power sensor can handle frequencies between 100kHz and 2GHz with powers of 1\mu W to 100mW.

Mixers

Mixers combine RF frequencies, either summing or subtracting them. Each mixer has 3 inputs

1. Local Oscillator(LO)
2. Radio Frequency (RF)
3. Intermediate Frequency (IF)

Switches

Mixer:

Subtraction:

Input 1: L

Input 2: R

Output : I=abs(L-R)

Addition:

Input 1: L

Input 2: I

Output: R=L+-I

Topics

• Measuring RF power
• Termination and impedance matching
• Attenuation and filtering
• Splitters, mixers, and switches