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Gough Lui's Blog

27 posts
In order to test the RTM3004, it was important to have something that generated signals that could be used to challenge the unit. I view testing the unit to be an important part of properly reviewing a product and using the inbuilt demo features or generators is often not sufficient to uncover deficiencies. As a result, I pulled together some of the scraps I had at home and all of the skills I had to generate some signals.   This part details some of the special-purpose programs and design ...
While the previous sections all looked at using the oscilloscope interactively, many users expect to use test equipment via remote control or as part of an integrated testing solution. Fortunately, the Rohde & Schwarz RTM3004 offers a USB device port and an Ethernet port for PC or LAN connectivity.   Setup Setup of the RTM3004’s connectivity is done through the on-screen menu. The unit is capable of either USB connectivity or LAN connectivity, but not both at the same time. If USB ...
The RTM3004 can be more than just an oscilloscope. With the addition of the RTM-B6 Waveform Generator and 4-bit Pattern Generator option, it’s possible to generate regular functions, modulated functions, bit patterns and arbitrary waveforms for testing devices from the oscilloscope itself.   Pattern Generator The RTM3004’s 4-bit pattern generator is output from four lugs on the front panel. This is not the most convenient form of connectivity if you’re looking to drive an ...
With modern electronics operating at ever-lower voltages and power efficiency being a prime concern amongst portable electronics, analysis of switching power converters is a common application for high-end oscilloscopes. While the RTM3004 can be used ordinarily to analyse such signals, this is made much easier with the RTM-K31 Power Analysis option which provides applications pre-configured for measurement tasks such as evaluating power quality, harmonics, inrush current, power consumption, slew ...
Another difference between an ordinary oscilloscope and a mixed domain oscilloscope comes down to the presence of digital input channels. In the case of the RTM3004, the RTM-B1 Mixed Signal option provides 16 digital channels to turn the RTM3004 into a mixed domain oscilloscope.   The Hardware The digital logic channels are connected to the right-hand side of the oscilloscope through two coax-ribbons which connect to two identical pods hosting eight channels each. As for which pod is design ...
Serial interfaces of a number of types are in common use in embedded systems and having the ability to analyse and troubleshoot these communications in the digital domain is one part of a mixed-domain solution. The RTM3004 has the following protocol decode options for triggering and decoding available as options at the time of writing: RTM-K1 for I2C and SPI RTM-K2 for UART/RS-232/RS-422/RS-485 RTM-K3 for CAN and LIN RTM-K5 for Audio (I2S, JK, RJ and TDM) RTM-K6 for MIL-STD-1553 RTM-K7 for ...
While on-paper specifications are easy to compare, they only tell part of the story. While a device might be excellent on-paper, it could be difficult to use or have a number of important limitations. In this section, I look at the usability aspects of the RTM3004 – just how enjoyable is it to use on a daily basis? Are there any annoyances which get in the way of getting things done?   Documentation As with all complex test equipment, I always recommend prospective users read the manu ...
Thanks to element14 and Rohde & Schwarz, I’ll be one of the three lucky people from the community to receive a fully-specced-out RTM3004. It was just as exciting as you can imagine, as it’s not every day you get a package like this. As a result, I even made preparations to welcome the package to my room.   So, for those who missed out and those that are genuinely curious as to what is included in the box, I’ll cover the unboxing in detail. I hope you all enjoy the pho ...
While the RoadTest is mainly concerned with the Rohde & Schwarz RTM3004 oscilloscope, it would be remiss of me to only focus on that particular unit, seeing as test equipment purchases are often a “big ticket” item where it may pay to shop around, especially as needs and applications vary.   As a result, I spent some time looking around the major suppliers (including Rohde & Schwarz, Tektronix, Keysight, Teledyne LeCroy and Rigol) to see what was on offer. The criteria ...
One of my regular blog readers submitted an LED globe for post-mortem analysis, having failed well before the expected lifetime. I take a look inside, determine the configuration and analyze the relatively "anonymous" product which seems to show several design shortcomings which I discuss and think might be relevant to other readers at the element14 community.   The article is posted at http://goughlui.com/2016/06/01/failed-click-ltmr5w3k-5w-led-mr16-replacement-globe/   What really ...
I suppose all the car owners out there love the luxury of having a remote keyfob to lock and unlock their cars, but periodically, they need their batteries replaced. Imagine my surprise when my Dad said that "the battery doesn't seem to be replaceable" ... when every remote I had met to date had a socket for some odd-ball A21 12v cell or a lithium coin cell.   Thanks to element14 and their prompt order fulfillment, we were on our way with nothing more needed than a soldering iron, desolder ...
As many hobbyists like to experiment with wireless devices, having a good 433.92Mhz transmitter is necessary to optimize the reliability of their systems and their range. While these modules can be finicky to use for data link purposes (and I won't go into that), they are quite simple for replicating remote control signals to control wireless switches, etc. To improve range and reliability, users often recommend buying a particular sort of module or increasing the input voltage I wanted to find ...
I couldn't help but wonder, based on the previous posting and the discussion, exactly how did the 1 million combinations come about? Also, what are the functions of the fixed bits? Are they fixed pre-amble as my experience would suggest? Are there more hidden channels in the equipment than are used by the senders and that I know of? Can it cope with over-speed transmissions, shortened repetition delay times, less repetitions?   I embarked on a journey of "knowledge" by building myself a ge ...
It's been a while since I've had the time to post anything around here. Luckily, I had recently just submitted my PhD thesis so that gives me a chance to take a short break and do some of the stuff that I like.   Recently, I came across a bunch of cheap remote controlled 433Mhz power sockets which I decided to pick up, tear down and reverse engineer on my blog site. Because of the recent discussions regarding remote control that I've been a part of on this forum, I thought it would be rath ...
Thanks to element14, I've managed to get my hands on a copy of the first hard-copy MagPi magazine. It's a great milestone for The Raspberry Pi Foundation and The MagPi. Seeing as many people around the element14 circles have already reviewed and blogged about The MagPi, I've decided to blog about it on my own site instead.   To find out what I think about The MagPi, head on over to http://goughlui.com/2015/08/19/surprise-package-the-magpi-arrives-by-air-in-hard-copy/ ...