Multichannel Frequency Synthesizer ATE System

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"It took our team 4.5 months to organize the project, design the ATE system architecture, develop, program, and install the system at the customer site. Using our ATE system, the customer can decrease the testing time by up to 30X and measure 25 parameters for 10-channel and 400 frequency steps (10 MHz to 6.6 GHz)."

- Davit Zargaryan, 10X Engineering LLC

The Challenge:
Design, develop, and deploy a flexible and precise automated test equipment (ATE) system for a 6-channel tunable and a 4-channel fixed-frequency synthesizer.

The Solution:
Using the LabVIEW graphical system design environment with NI RF hardware to develop a flexible and high-speed ATE system that uses the latest technology and saves time and money.

Author(s):
Davit Zargaryan - 10X Engineering LLC

About 10X Engineering

10X Engineering LLC, founded in 2013, is an NI Alliance Partner with the knowledge and experience to deliver innovative engineering solutions for RF product (units, devices, components) quality and line testing, custom-designed ATE system assembly, verification, and development. Our solutions cover a variety of industrial sectors such as RF software defined radio, radiolocation, spectrum monitoring, and more. For every request we receive, we follow procedures for technical and software functional requirements clarification, RF measurement methodology selection, and hardware configurations. If needed, we take responsibility to prove a concept and demonstrate the flexibility and reliability of our solution.

Problem Background and Solution

Our customer designs and manufactures high-performance RF signal sources using frequency synthesis techniques for generating an output frequency, which support a wide range of commercial and industrial RF applications. The customer’s device under test (DUT) superficial testing includes 10 measurements at three frequencies (the start, middle, and end frequency of the synthesizer’s tunable bandwidth). This requires 5–8 hours of time from a professional engineer. The DUT also supports pulse modulation through two input TTL channels.

Individual test design, manual assembly, system calibration, and reporting are the most time consuming procedures for DUT engineers. Our company has developed a 12-channel frequency synthesizer ATE system with testing capabilities from 10 MHz to 6.6 GHz.

List of measurements include:

  • Output signal frequency range
  • Maximum frequency deviation from nominal value
  • Output power
  • Frequency setting time
  • Amplitude modulation depth
  • Amplitude-frequency response (flatness) in tunable bandwidth
  • Delay instability of an output RF pulse versus input synchronization pulse
  • Rising\falling edge delays of an RF pulse versus input IF pulse rising\falling edges
  • Radio pulse rise and fall time
  • RF pulse amplitude flatness
  • Radio pulse amplitude instabilities generated in .5 s phase noise, offsets from the carrier 1 kHz, 5 MHz
  • Output signal amplitude noise
  • Spurious emissions, harmonics, and subharmonics

We included a DUT control program along with automated report generation in the software.

The system requires the following NI equipment:

The customer’s synthesizer phase noise was sufficiently low at 120 dB c\Hz in 800 MHz. With our current configuration, users can achieve residual FM specifications, low nonharmonics, and excellent SSB phase noise up to -135 db c\Hz (800 MHz, 10 kHz offset).

Advantages of Phase Noise Measurement on NI PXIe-5663 (External LO Mode) and QuickSyn Configuration

Small random fluctuations or uncertainty in the phase of an electronic signal cause phase noise. We specify and measure phase noise because it is a fundamental limitation in system performance. We focus primarily on phase noise in the frequency domain, but phase noise can also be quantified as jitter in the time domain. There are several methods for measuring phase noise, but one of the most popular is to measure it using a spectrum analyzer and the 2-port correlation method to achieve high accuracy. In our system, we use a spectrum analyzer as it is also used in other measurements. We do not need to add new devices, which would increase the cost of the system.

The traditional approach to this issue, using the NI spectrum analyzers, was not enough for the phase noise carriers of these analyzers (1 GHz 1 k offset):

  • NI PXIe-5663: 100 dB c\Hz
  • NI PXIe-5665: -120 dB c\Hz, where the customer’s requirement is -120 dB c\Hz

After investigating the issue we found that we can use the NI PXIe-5663 (external LO mode) and QuickSyn configuration as it has a single LO input (easily substitutable with external one) and QuickSyn, which has the best phase noise in the class -135 dB c\Hz.

Figure 4 shows the phase noise performance of the NI PXIe-5663 and QuickSyn system. In order to measure the system’s phase noise we take as a DUT, NI PXIe-5653 3.6 fixed LO 800 MHz output. As NI PXIe-5653 phase noise is -145 dB c\Hz, what is lower than the NI PXIe-5663 and QuickSyn system shows the measuring system’s phase noises.

Conclusion

It took our team 4.5 months to organize the project, design the ATE system architecture, develop, program, and install the system at the customer site. Using our ATE system, the customer can decrease the testing time by up to 30X and measure 25 parameters for 10-channel and 400 frequency steps (10 MHz to 6.6 GHz).

Author Information:
Davit Zargaryan
10X Engineering LLC
Hovsep Emin 123
Yerevan
Armenia
Tel: (+374)77212193
zargaryandavid@yahoo.com

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