Even in an ever increasingly digital world, functional testers will always be required to measure analogue voltages and currents. Often these measurements are simply DC, and easily measured, but AC signals also need measurement in many applications, especially when audio is involved (e.g. set-top box, voice systems, etc).
The industry standard way to measure these signals is with a True RMS type measurement, but why?
Well the answer is quite simple. It is because RMS is the only AC voltage reading that does not depend on the shape of the signal being measured. For example, some test engineers will simply average a waveform, to ground, and then measure the result with a DC measurement system… yes, easy… but consider:
1) A 2Vpp symmetrical signal going from -1V to +1V will average to zero… not very good for testing if a circuit is working
2) A 2Vpp sine* wave going from 0V to +2V will average to 1V, but so will a square* wave and so will a triangular* wave.
These are extremely simple examples, but you can read more about why RMS measurement is really the only true way to measure AC signals by searching the web.
With the J-Testr, measuring True RMS AC signals is easily achieved using the compact, 4cmx3.5cm, four channel “AC Measurement Module” which has 4 multiplexed AC inputs, two channel selection lines, a DC analogue output and a digital frequency output. The selection lines and output signals simply connect back to the standard high accuracy ADC/DAC peripheral card such as to enable RMS and frequency measurements for 4 signals.
The module is supplied with everything needed to easily and quickly mount onto the customer’s interposer card. Please see the module instructions for more information by clicking here.
The really unique feature of the module is that, as all J-Testr peripherals can be accessed via JTAG*, accurate AC measurements can be made directly from JTAG tools when/if required. This further helps manufactures to leverage more value from their ‘high value’ JTAG tools, and helps extend test coverage without moving away from their preferred JTAG tools.
*Access is via Ethernet or JTAG.
The market for RF enabled devices is increasing rapidly, and they are finding their way into a diverse range of products and market segments ranging from to very low volume to very high volume. This increase is driven by the popularity of WIFI, Bluetooth and ZigBee communication standards, among others, which now can be implemented very costeffectively with either SOC or module based solutions.
Functional testing of these RF devices is often thought to be an extremely complex and expensive task. RF enabled
devices are often either inadequately or excessively tested due to a lack of understanding of what actually needs to be tested, and how it can be tested.
Eiger Design has written a document that briefly highlights some of the considerations and solutions available to test engineers to help them achieve the best test solution, in terms of cost and complexity, when dealing with RF enabled devices.
Follow the link to find out more <Testing of SOC based RF devices>
Many test applications require a fixture to provide pin contacts to the UUT. With the new J-Testr+ concept, the J-Testr can be fitted inside the fixture with little effort, providing a very neat and compact solution with minimal cables.
With rear connections and access to the interposer, external equipment can be easily accessed, in the case below an Ethernet hub is powered directly from the J-Testr 5V eliminating unnecessary and untidy cabling.
The latest version of the J-Debugr version includes:
1) Improved connection response on Windows 10
2) Register name tool tip active on 'Read' button and 'Value' spin box to assist locating correct register to read a value or make a value change
3) Minor small bug and text amendments
Please see at in <Downloads>
Powering up UUT for the first time can be a risky business as there could be failures, such as shorts between supply lines, that could mean the UUT will never work or require significant expensive reworking. This is especially important when the UUT contains very expensive parts such as high end FPGA or micro processors.
A good test setup should have features to help the user protect the UUT from over-currents and over-voltages in a quick (micro seconds) and controlled manner.
Read more about the problem in the Technical Report <UUT Power up Safety>
Is your UUT protected and safe?
Testing UUT power supplies is often discarded as not required with the thought that 'if it works' the power must be ok. Nothing could be further from the truth as power supplies are often complex analogue circuits with multiple failure mechanisms.
Eiger Design has written a Technical Report explaining more and the risk involved when not properly testing the power supplies within a UUT.
Follow the link to find out more <UUT Power Testing>