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New AXIe and PXIe High-Speed Digitizers Blog Platform for T&M Applications

Network with Robin Hassell at Photonics West 2017, San Francisco, California, USA, 28 January – 2 February

Robin Hassell, Business Manager for Keysight High-Speed Digitizer Technology will introduce you to the latest developments on Swept-Source (SS-OCT) application options and PCIe digitizers.

For more information about the exhibition:

Robin Hassell’s contact details: +1 (940) 602 0860 e.mail:


Streaming and Recording Application Options for U5303A High-Speed Digitizer: An Example (2/2)

In the following example, we capture 2 channels simultaneously at 1 GS/s with signal at 1.8 GHz center frequency  and 200 MHz IBW  

Sampling and compliancy with Nyquist zones

– The IBW is in 4th Nyquist band (between 1.5 GHz and 2 GHz) and doesn’t cross over between Nyquist zones

– For signal in 4th Nyquist band, sampling at 1 GHz Fs  causes an aliased signal in negative frequency domain . This aliased signal is then down-converted in baseband

Filtering requirements

– It is recommended to add a pass-band filter at the digitizer input, selecting the signal IBW (1.7 GHz to 1.9 GHz)

Local Oscillator

– For down conversion, LO would be set at signal center frequency 1.8 GHz  (physically the signal is aliased at -200 MHz, thus LO is at -200MHz).

IBW and data rate

– The signal 200 MHz IBW  requires to select higher decimated sampling rate 250 MS/s, resulting in a 1000 MB/s data rate

Multi-channel streaming

– Using U5303A-CB1: a single digitizer can manage the 2 channels simultaneously since streaming limit is 2.4 GB/s

– Using M9703B-CB1: streaming limit is 1.5 GB/s, thus there are two solutions to stream 2 channels simultaneously

   – either use two digitizers

   – or a single digitizer with 12-bit mode: this case results in two channels at 700 MB/s per channel with resolution: I – 12 bits, Q – 12 bits

To learn more about Keysight Application Options, please contact us at



Frequency Analysis Measurements with the New 10-bit PCIe Digitizer

Up to 10 GS/s and more than 2 GHz Instantaneous Bandwidth per Channel

Key Features:

-One channel at 10 GS/s or two channels at 5 GS/s, DC up to 2.5 GHz bandwidth

-Dual full scale range 250 mV and 1 V

-Low noise density, low distortion and optimized frequency response flatness


Keysight High-Speed Digitizers Team announces capability of more than 2 GHz instantaneous bandwidth on the U5310A 10-bit PCIe high-speed digitizer.

This unique ADC card is designed for frequency analysis such as wireless, telecommunication and spectroscopy applications.

The new U5310A high-speed digitizer features one channel at 10 GS/s or two channels at 5 GS/s, DC up to 2.5 GHz bandwidth and dual full scale range at 250 mV and 1 V.

We developed proprietary ICs for the U5310A. In particular, low noise and low distortion signal conditioning amplifier to drive interleaved ADCs and specific clock distribution to minimize the clock jitter and spurious. Moreover, optimized frequency response flatness provides enhanced measurement accuracy.

“With those proprietary technologies, Keysight provides the unique solution to interleave DC coupled 10-bit ADCs without adding distortion while providing low full scale and wide bandwidth input” said Daniel Frund, Analog and IC Design Manager, Keysight’s Digital and Photonics Center of Excellence.”

Here below some examples of frequency analysis measurements:

1) Frequency response (nominal) to a 100 MHz single tone input signal at -1 dBFS, acquired at 5 GS/s, without equalization, and using 1V FSR.

U5310A-Frequency-Response-100 MHz-single tone input signal


2) Frequency response (nominal) to a 1.9 GHz single tone input signal at -1dBFS, acquired at 5 GS/s, without equalization, and using 1V FSR.

U5310A-Frequency response-1.9-GHz-single-tone-input-signal-at -1dBFS


3) Frequency response (nominal) to a 1.9 GHz single tone input signal at -1dBFS, acquired at 10 GS/s, without equalization, and using 1V FSR.


For more information about Keysight High-Speed Digitizers, please contact us at



Streaming and Recording Application Options for U5303A, M9703B and M9203A High-Speed Digitizers (1/2)

The following application options offer multichannel digital down-converter streaming and recording and enable continuous gapless acquisition, implementing:

– Real time multichannel phase coherent digital down converter

– Data steaming to host

– Multichannel recording to disk all I/Q samples for later analysis

Keysight solution includes a high-speed digitizer, a configured PC workstation, a data storage system configured and qualified. The system depends on the selected format AXIe, PXIe, PCIe.

Digital Down Conversion (DDC): This is real-time firmware (FPGA code) capability to reduce the amount of data to be transmitted, by selecting a programmable instantaneous bandwidth centered around a programmable center frequency, shifting it down and decimating to a lower sample rate. This firmware capability is operating synchronously on all acquisition channels.

CB1 / CB2 principle

Digital Down Conversion

The digital down converter (DDC) mode of the digitizer allows to convert a digitized real signal centered at a center frequency1 (Fc) to a baseband complex signal. In addition to down conversion, DDC decimates to a lower sampling rate, allowing follow-on signal processing by lower speed processors.

Process in frequency domain

When a signal is acquired by a digitizer, aliased images appear at frequencies depending on sampling rate frequency (Fs) due to sampling and folding-back (See example in Fig.2). The aliased signal in 1st Nyquist zone is used for down-conversion and translated in baseband thanks to Local Oscillator (LO) at configurable center frequency (Fc). Then, digital Low-Pass Filtering (LPF) is used to remove some unwanted aliased signal. The baseband signal is decimated then used for streaming and recording.

Figure: Example of a signal acquisition in 3rd Nyquist zone
Sampling causes initial signal in Instantaneous Bandwidth (IBW) to be aliased–back in 1st Nyquist zone. Then, using LO at Fc, the resulting baseband signal is used for streaming.


CB1 / CB2 usage and guidelines

Filtering of input signal

At sampling, unwanted signal in other Nyquist bands can create unexpected aliased signals in the working bandwidth. This could deteriorate the signal once translated in baseband.

To limit this aliasing effect, it is recommended to add a band-pass filter at the digitizer input. Its bandwidth value should select the signal of interest. The filtering may become mandatory if the signal has several carriers .

Sampling Frequency & Instantaneous Bandwidth

Due to aliasing, the Instantaneous analysis Bandwidth (IBW) of input signal must not overlap on two Nyquist zones —Nyquist zones are limited by frequencies multiples of Fs/2 .

Here an example :



Streaming: This is the capability of the digitizer to continuously send data to the controlling host while the acquisition is still running.
Recording: This is the capability of the system to send data continuously from the host to a storage device.

CB1/-CB2/-CB3 application options: These bundle options for the U5303A or M9703B digitizer provides a real-time digital down-converter (DDC) and I/Q data streaming together with recording capabilities.

Local Oscillator (LO): The DDC uses a programmable Local Oscillator to mix sampled signal with the selected center frequency

Keysight at Jaisis Japan 2016

Our partner Acquiris Japan presents our SS-OCT and Streaming and Recording Solutions at JAISIS Japan, one of the largest exposition in Asia for Analytical and Scientific Instruments.