I'm using the E4438C as a baseband generator to generate an unmodulated sine wave at baseband frequencies. I expect the signal to be output at the rear-panel I/Q ports but no signal is output. I'm working at a BB frequency (~10MHz) and when I use the RF port, my sine wave is output (I then use a phase shifter to split it to I and Q, but I want to remove the phase shifter from my setup).
When I modulate the signal (using a ARB waveform generator) then I get the correct signal at the I_out and Q_out ports.
Is there anything I need to do in order to enable signal output at the I_out and Q_out ports, or are they reserved only for modulated signals?
Thanks,
David
When I modulate the signal (using a ARB waveform generator) then I get the correct signal at the I_out and Q_out ports.
Is there anything I need to do in order to enable signal output at the I_out and Q_out ports, or are they reserved only for modulated signals?
Thanks,
David
The rear-panel I/Q ports output the analog in-phase component of I/Q modulation signal, but it has to come from the internal baseband generator.
Other things to take note of on the I/Q ports:
The nominal output impedance of this connector is 50Ω, DC-coupled.
The damage levels are > +3.5 V and < −3.5 V.
The DC origin offset is typically < 10 mV.
The output signal levels into a 50Ω load are as follows:
• 0.5 Vpk, typical, corresponds to one unit length of the I/Q vector.
• 0.69 Vpk (2.84 dB), typical, maximum crest factor for peaks for π/4 DQPSK with alpha = 0.5.
• 0.71 Vpk (3.08 dB), typical, maximum crest factor for peaks for π/4 DQPSK with alpha = 0.35.
• Typically 1 Vp-p maximum
Regards -