Automated test systems are common in high-volume manufacturing environments. These automated systems have been embraced because of their ability to decrease time-to-market, minimize design iterations, improve repeatability, and reduce the cost of testing. Spectrum analyzers make up a key part of most automated test systems for wireless products. With wireless capabilities becoming nearly ubiquitous in a wide array of products, spectrum analyzers are becoming a more integral part of automated test systems. Spectrum analyzers play a role in assessing the performance of the wireless products, as well as in verifying that the products meet RF regulatory compliance standards. In this article we’ll look at some defining features of spectrum analyzers and identify important product specifications (specs) for ensuring a precise, reliable, and efficient automated test solution.
What exactly is the role of a spectrum analyzer in an automated test system?
An automated test system uses software-driven test equipment to run predefined tests on a product – sometimes a large volume of products – without human intervention. These tests may run continuously during the development process or be executed at the end of the manufacturing process to ensure product quality and compliance before packaging and shipping. The test equipment included in the automated system may include spectrum analyzers, network analyzers, or signal generators. Spectrum analyzers play a crucial role in automated test systems for wireless products, due to their ability to monitor, analyze and record RF performance of the devices under test (DUTs).
Spectrum analyzers can be used to monitor the frequency spectrum of the DUTs to verify they are operating within their intended frequency and that any spurious emissions fall within acceptable limits. This is important for ensuring the signal quality of the product and verifying that the product complies with regulatory requirements. Spectrum analyzers can also be used for modulation analysis such as WLAN modulation, or digital modulation, and performing EVM measurements to locate excess noise or non-linearities in the signal. These metrics ensure the device is transmitting signals as intended.
How important is measurement speed in a high-volume environment?
When selecting a spectrum analyzer for use in an automated test system, measurement speed is a key specification to consider, especially in a high-volume development or manufacturing environment. Sweep speed is defined as the amount of spectrum the analyzer can cover in GHz divided by how long it takes. Spectrum analyzers with fast sweep speeds, such as Signal Hound’s SM series (SM200B, SM200C, SM435B, and SM435C) with sweep speeds up to 1 THz/second at 30 kHz RBW, can ensure an efficient testing process, preventing bottlenecks during the testing process. In addition to increasing efficiency, fast sweep speeds increase the likelihood of catching transient signals and reducing the effects of time-sensitive factors like signal drift and environmental variations for more precise measurements.
How do dynamic range and sensitivity affect the outcome of product verification?
Another important spec to consider when selecting spectrum analyzers for an automated test system is the dynamic range. The dynamic range affects the sensitivity of the spectrum analyzer. A wide dynamic range allows the spectrum analyzer to capture very weak signals, even in the presence of stronger signals. This is important for any DUTs that transmit a range of signals, such as short-range Bluetooth communications and long-range WiFi or Cellular communications. Signal Hound’s SM series offers a wide dynamic range of 110 dB, paired with ultra-low phase noise, making these spectrum analyzers an excellent choice for precision RF analysis and ensuring product quality and compliance.
What makes a spectrum analyzer easy to integrate into an automated test system?
Integrating test equipment into an automated test system can be tricky. Not all equipment plays nicely with each other or with 3rd-party software. In the case of integration, the key lies in the software capabilities. Many spectrum analyzers utilize a built-in software interface for device control. Depending on the API or scripting capabilities, this may create difficulties during integration. Signal Hound’s SM series of spectrum analyzers offers free Spike™ software that provides full device control, a configurable spectrogram display and user interface, and a variety of analysis modes. Signal Hound exposes a programming layer for each device sold, allowing for headless operation using an API. This allows customers to write custom applications specific to their needs. These APIs have also spawned a small ecosystem of third-party software that services other industries.
In addition, Spike provides an interface for the remote operation of Signal Hound devices by sending Standard Commands for Programmable Instruments (SCPI) commands through a TCP/IP link. You can connect/interface with your Signal Hound device via Spike through any Virtual Instrument Software Architecture (VISA) implementation or any programming language that allows SOCKET programming. Customers can write automation scripts using the industry standard SCPI commands to control Spike. SCPI provides a common syntax, command structure, and data interchange format which can be used across multiple SCPI compatible test and measurement instruments. These capabilities are commonly adopted and used in manufacturing and R&D applications.
Download our tech brief, SCPI Automation of Signal Hound Spectrum Analyzers to learn more about remote interface and control capabilities using SCPI compatibility commands for Signal Hound’s spectrum analyzers via its Spike software.
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Assessing spectrum analyzer value: reliability and the cost-performance balance
Determining the value of a spectrum analyzer is a process based on individual needs. The first step in this determination is assessing the importance of three main factors for your test system – performance, reliability, and cost. To assess performance needs, you’ll need to know the frequency range your spectrum analyzer will need to monitor. You will also need to know what types of signals need to be measured. Does the DUT transmit short-range, weak signals along with stronger long-range signals? If so, you’ll want to ensure that your spectrum analyzer has a wide dynamic range. Fast sweep speeds are generally beneficial, but how fast is fast enough for your needs? Another factor to consider is the reliability of equipment and the ease of replacement. Signal Hound stands behind the reliability of their equipment with a standard two-year warranty on all products and has an excellent reputation with customers for fast turnaround times on repairs. Lastly, you’ll need to consider the budget allocated for test equipment and find a balance between the performance required and the cost of equipment.
Conclusion
Utilizing an automated test system to verify wireless product quality and compliance is an efficient way to test products in a high-volume manufacturing environment and can decrease time-to-market. Signal Hound’s innovative spectrum analyzers are ideally suited for automated test systems. The SM-series offers performance rivaling even the most expensive spectrum analyzers on the market. The free proprietary software offers many useful analysis modes and offers an interface for the remote operation of Signal Hound devices. If you’re integrating our SM-series devices into a larger system, Signal Hound provides useful documentation and resources such as data sheets, user guides, 3D models, and more.
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