Agilent Technologies E4406A manual Selecting Input Probes for Baseband Measurements

Making Measurements

Using Baseband I/Q Inputs (Option B7C)

Selecting Input Probes for Baseband Measurements

The selection of baseband measurement probe(s) and measurement method is primarily dependent on the location of the measurement point in the circuit. The probe must sample voltages without imposing an inappropriate load on the circuit.

The following four measurement methods may be used with baseband I/Q inputs:

•50 Ω Unbalanced - This is the measurement method of choice if single

ended or unbalanced baseband I and/or Q signals are available in 50 Ω coaxial transmission lines and are terminated in a coaxial connectors. Adapters necessary to convert to a 50 Ω BNC male connector must be of 50 Ω impedance. The methods are as follows:

—I only measurement using one single-ended probe connected to the I input connector

—Q only measurement using one single-ended probe connected to the Q input connector

—I/Q measurement using two single-ended probes connected to the I and Q input connectors

•600 Ω Balanced - This is the measurement method of choice if balanced baseband signals having a 600 Ω impedance are available. The methods are as follows:

—I only measurement using one differential probe or two single-ended probes connected to the I and I inputs

—Q only measurement using one differential probe or two single-ended probes connected to the Q and Q inputs

—I/Q measurement using two differential probes or four single-ended probes connected to the I, Q, I, and Q input connectors

156 Chapter 4