This is the decade of mobile broadband: seemingly everyone and everything is connected to the Internet, and all need to exchange more and more data. As today’s electronic devices become smarter, they contain more functionality, are more highly integrated and manage much greater volumes of data. Enabling access to anything from anywhere—while moving huge amounts of data—is one of today’s most daunting challenges.

As electronic devices evolve, so must the instruments used to test them. With the tighter specifications of high speed devices, testing is no longer an option: it’s mandatory.

To stay ahead of the curve, today’s test instruments must have the following attributes:

  • Reach higher frequencies while providing wider bandwidth
  • Handle complex modulation techniques needed to cram more data into available bandwidths
  • Work with ideal and real-world signals
  • Stress devices to their limits
  • Provide reliable and repeatable results

Focusing on AWGs

Taking these typical test requirements into consideration, an AWG might seem to be the perfect stimulus device. The M8195A is a new arbitrary waveform generator with the highest combination of sample rate, bandwidth and channel density currently available. It provides up to 65 GSa/s, 20 GHz analog bandwidth and up to four channels in a one-slot AXIe module – simultaneously.


Figure 1

Figure 1 16 QAM @32 Gbaud.

As optical communication data rates move from 100 to 400 Gb/s and 1 Tb/s, they require a very wideband electrical stimulus with a variety of complex modulation formats from QPSK, to any quadrature amplitude modulation (QAM), to orthogonal frequency-division multiplexing (OFDM) at symbol rates up to 32 GBaud (see Figure 1) and beyond.

In order to drive dual-polarization systems, the M8195A has four independent, precisely synchronized output channels in a single AXIe module. Since all four channels are generated by the same instrument without any external circuitry, precise synchronization down to the femto-second-range can be achieved and maintained.

Figure 2

Figure 2 PAM 4 signal at 28 Gbaud (=56 Gb/s).

The M8195A uses digital pre-distortion techniques to achieve a clean signal out-of-the-box and at the device under test. Distortions generated by cables, amplifiers etc. can be compensated by embedding/de-embedding the S-parameters of the respective circuits or by performing an in-situ calibration.

Digital interfaces are facing increasing data throughput as well. Traditionally this has been accomplished by increasing the data rate or by increasing the number of parallel signals. However, at a certain point in time, it is more cost-effective to consider multi-level signaling techniques. Examples are high-speed backplane connections using pulse-amplitude modulation 4 (PAM4) (see Figure 2) or PAM8 modulation formats, but also technologies in the mobile application space such as MIPI C-PHY.

Figure 3

Figure 3 32 Gb/s PRBS211-1 showing 138 fs RJ (rms) generated by the Keysight M8195A.

The M8195A is well suited to address these multi-level and multi-channel interfaces using any standard or custom data format. The flexibility of the waveform generation at highest speeds, combined with excellent intrinsic jitter performance (see Figure 3), makes the M8195A a future proof instrument – independent of which direction the technology is moving.

At data rates of multiple Gb/s, the effect of cables, board traces or connectors have to be taken into account in order to generate the desired signal at the test point of the device under test. The M8195A incorporates digital pre-distortion techniques to generate the desired signal at the device under test. Channels can be embedded / de-embedded with the S-parameters of the respective circuits. With up to four differential output channels per one-slot AXIe module and the ability to synchronize multiple modules, the M8195A is well suited to stimulate multi-lane high speed interfaces in an economic fashion.

Physics, chemistry and electronics research working at the edge of technology, call for precise and configurable pulses down to 100 ps or less for extremely short, yet wideband RF pulses and chirps. Any arbitrary waveform which can be described mathematically can be generated e.g., in Matlab and downloaded to the M8195A.

Figure 4

Figure 4 Multi-tone signal from 10 to 15 GHz.

EW and communications/satcom applications require extremely wide instantaneous bandwidth from DC to the Ku-Band. In addition, jamming requires fast frequency hopping across bands within hundreds of picoseconds.

The M8195A is designed to address these requirements.  With built-in frequency and phase calibration, it is straightforward to generate wideband multi-tone signals (see Figure 4) with a flat frequency response up to 20 GHz with the M8195A. Wideband wireless signals with any modulation scheme (e.g., nPSK, nQMA, OFDM, etc.) can be generated directly at carrier frequencies of up to 20 GHz. In many cases, this saves an additional up-conversion stage or enables waveform generation directly at the carrier frequency.

M8195A at a glance

As devices and interfaces become faster and more complex, the M8195A AWG gives you the versatility to create the signals you need for digital applications, optical and electrical communication, advanced research, wideband radar and satcom. The M8195A gives you the possibility to test where you have never been able to test before in speed, in bandwidth and in channel density.

Key features of the M8195A:

  • Sample rate up to 65 GSa/s
  • Analog bandwidth to 20 GHz
  • 1, 2 or 4 channels in one slot AXIe module

New technologies make it possible to adapt to evolving test requirements. This is especially true with next-generation arbitrary waveform generators, such as the M8195A that offer wide bandwidth and high resolution. These technologies enable the creation of precise time-domain signals and provide the flexibility to address many applications typically covered by function or pulse generators.  In the frequency-domain, AWGs have been used to generate baseband signals. Now, they are also moving into RF applications, not only due to high sampling rates and analog bandwidths, but also high signal quality in terms of spurious free dynamic range (SFDR) and phase noise performance.

Keysight Technologies Inc.
(formerly Agilent Technologies electronic measurement business)
Santa Rosa, Calif.