8 Results
PAM-4 (4-level pulse amplitude modulation) has been introduced in high-speed serial data technology to reduce the bandwidth demands of ultra-high data rates. It uses only half the bandwidth per bit that would be required of conventional NRZ (non-return to zero) modulation. But at the same time, PAM-4 signaling complicates design and test at every turn. Evaluation of channels is now just as important to system development as serializer / deserializer (SerDes) testing and the challenges presented require a higher level of test and measurement performance than ever before. This paper investigates the evaluation complexities of PAM-4 interconnects at high data rates.
Load pull is a powerful method for characterizing RF power amplifiers through impedance variation. Load pull enables model extraction and validation as well as performance, ruggedness and efficiency testing.
Vector Network Analyzers of t ZNA and ZNB family are able to measure magnitude and phase of complex S-parameters of a device under test (DUT) in the frequency domain. By means of the inverse Fourier transform the measurement results can be transformed to the time domain. Thus, the impulse or step response of the DUT is obtained, which gives an especially clear form of representation of its characteristics. For instance, faults in cables can thus be directly localized. Moreover, special time domain filters, so-called gates, are used to suppress unwanted signal components such as multireflections. The measured data "gated" in the time domain are then transformed back to the frequency domain and an Sparameter representation without the unwanted signal components is obtained as a function of frequency. As usual, other complex or scalar parameters such as impedance or attenuation can then be calculated and displayed.
The R&S®ZNA vector network analyzer with the integrated LO output option provides a simple, cost-effective solution for 2-port and 4-port measurements using Rohde & Schwarz mmWave converters.
Many applications in aerospace and defense as well as in mobile communication require a defined magnitude and phase relation between several signals, for example, to design a smart antenna array and it's distribution network, or to ensure accurate phase alignment between different transmitter or receiver chains of T/R modules. Magnitude can be measured with spectrum analyzers or power meters. For phase measurements, a vector network analyzer is the easiest, fastest and most accurate instrument.This application note shows how to measure the phase accurately between several signals using vector network analyzers of the R&S®ZNA, R&S®ZNB and R&S®ZNBT families.
Frequency converters e.g. in satellite transponders need to be characterized not only in terms of amplitude transmission but also in terms of phase transmission or group delay, especially with the transition to digital modulation schemes. They often do not provide access to the internal local oscillators. This application note describes a method using the R&S®ZNA analyzer family to measure group delay of mixers and frequency converters with an embedded local oscillator very accurately. The key aspect of this new technique is that the network analyzer applies a 2-tone signal to the frequency converter. By measuring the phase differences between the two signals at the input and at the output, it calculates group delay and relative phase.
The R&S®ZNA vector network analyzer offers a dynamic range that is unbeatable on the market. This kind of sensitivity unlocks potential applications that previously could not be addressed with a vector network analyzer.
Versatile Software Tool for Rohde & Schwarz Instruments RSCommander is a versatile software tool for a wide range of Rohde & Schwarz spectrum-, network analyzers, signal generators and oscilloscopes. It allows for automatic instrument discovery, making screenshots, reading traces, file transfer and simple script creation.