Vector Signal Generator Basics - Part 2
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In Part 1, we explored real-time waveform generation, which enables verification of receiver designs in all stages, from baseband subsystem coding to sensitivity tests. We also looked at each component in a baseband generator. In addition, we discussed additive white Gaussian noise (AWGN) and channel emulation for simulating realistic channel conditions between a transmitter and a receiver. These enable receiver performance and functionality testing during radio-frequency (RF) and baseband integration or system-level tests.
The real-time waveform generation mode characterizes receiver performance of specific wireless standards. But not all wireless standards require such a long-period signal for receiver testing. For example, Wi-Fi IEEE 802.11ax specifies the minimum input sensitivity with a certain package error rate. The signal is in a packet and frame format. You can generate a waveform segment that includes one or several packets, then repeat the segment. The receiver gets the signal and uses cyclic error-correcting coding to determine whether each packet is corrupted.
Transmitter and component tests verify physical-layer performance. Relevant test signals are payload independent, so they don’t require a long-period signal. Waveform playback mode lets you quickly generate a complex signal to characterize the transmitters and components.