Friday, March 24, 2017

Latest Saelig Newsletter - Highlights Pico Technology!

The latest Saelig Newsletter focuses on Pico Technology news: their new 4444 4-channel differential scope and novel probes, new helpful tech videos, as well as useful tech tips.

It's here:

Thursday, March 23, 2017

New Rigol Support Helps

Rigol has published lots and lots of new app notes and videos to describe in detail the use of their products.  77 articles on scopes alone! 58 on spectrum analyzers, 39 on waveform generators.  Quite a gold mine!  features lots of helpful app notes & articles.

Lots of short training videos are:

Rigol also refers to other Channels which exhibit Rigol stuff:

And they have a new logo:

"Beyond Measure" has gone away and now it's "Innovation or Nothing". 

Monday, March 20, 2017

Using the AMETRIX Model 101 to Investigate Leakage Currents in Clamp Diodes

Clamp diodes are widely used in analog electronic circuits. Like all real-world components, these diodes have some non-ideal characteristics; this paper investigates some of these characteristics for a few diode candidates. The AMETRIX® Instruments’ Model 101 Picoammeter is used for measuring these small currents.
Reverse biased leakage current is a characteristic of concern for a clamp diode. Ideally the leakage would be zero but this is the real world, so what can one live with? In a typical application there might be two clamp diodes, one to +15 V the other to -15 V and a common connection to the signal to be clamped. The leakage current drops as the voltage drops, so if that signal is nearer to +10 V, then the lower clamp diode would have more leakage than the upper one. So in such an application, a diode with both low leakage and a fairly flat leakage vs. voltage would be desirable.

Figure 1 is plotted data of leakage measurements versus reverse voltage. A quiet DC supply was used along with an AMETRIX Instruments’ Model 101 Picoammeter to measure the current (and yes, that is single-digit femptoamps you are seeing).
Comments about reverse leakage:
1.    The SST4391 is rated for 35 V gate-drain and gate-source
2.    The SST4391 costs $0.057 each
3.    The 2n3904 has a Vcb maximum of 60 V
4.    The MMBT3904LT1G is $0.0231 each
5.    The FLLD261 is $0.0275 each
6.    The BAS16 costs $0.0151 each
7.    The BAT54 costs $0.0204 each
8.    The BAS70 costs $0.0323 each
9.    The MMBD4148CC costs $0.0194 each
So even though there is a 3:1 price ratio between the most and least expensive, they are all < 6¢, so cost is probably not a serious part of the decision process.
The forward voltage drop is another diode characteristic to be considered for a voltage clamp. These measurements were made as follows (the data is presented graphically in figure 2):
1.    Forward bias the diode with a quiet DC supply that has fine resolution; in this case an EDC calibrator
2.    With function generator set to pulse, 1 Hz, 1% duty cycle, drive a mercury wetted reed relay. Connect the relay contacts across DUT such that the DUT is shorted for 990 msec and unshorted for 10 msec; this is to minimize self heating effects.
3.    Measure forward voltage with Tektronix MSO4104 scope with Model 100 Series' probes to minimize the low forward current errors. Set the scope’s bandwidth limit to 20 MHz to minimize noise. Use the scope’s vertical channel’s offset mode and 10 mV range, adjusting the offset knob until trace is in center of screen, then document the offset voltage.

In conclusion, some simple measurements can provide much insight into the components that you think might be ideal in a given application; and they might reveal some things that are unexpected.

Friday, March 17, 2017

Why USB RF Signal Generators Should Be in Your Next Project

Low-cost Universal Serial Bus (USB) radio frequency (RF) signal generators have recently
come on the scene in the wireless world. They promise to be game changers for many
reasons. Until these devices came out, a prospective buyer had two choices when it
came to RF signal generation solutions. The buyer could either purchase a $20K+
benchtop box with all the bells and whistles, or they could purchase a $6K narrowband
“synthesizer”, either hard coded to one frequency, or with an RS-232 programming port
to figure out. Both of these solutions would typically take eight weeks to deliver. They
are generally build-to-order components.
USB RF signal generators are actually a hybrid approach to both of those options
mentioned above—they can be much cheaper and deliver in a couple of days.
A great (made in the USA) example is the Windfreak Technologies SynthHD
Dual Channel Microwave Signal Generator
for $1,279. This price is surprisingly cheaper than some RF test cables.
MSG Microwave Signal Generator


The device has two independent channels that can tune in 0.1 Hz increments from
54 MHz to 13.6 GHz. The SynthHD’s RF power is adjustable in .01 dB increments
from -50 dBm to +22 dBm. It also has many modulation features including FM chirps.
The relative phase between the two channels can be adjusted in .01 degree increments.
It is a hybrid approach because the device can either be controlled
with a PC graphical user interface (GUI) like benchtop test and measurement (T&M)
equipment, or it can be programmed to function as a module inside a communication
system without a PC, like the narrow band synthesizer mentioned above.
The SynthHD signal generator will generate sweeps. The sweeps can be single
channel or dual channel. The device can sweep up or sweep down. It can also ramp
up or down amplitude while sweeping. The sweep can be controlled with an external
trigger to either perform a full sweep per trigger, or perform a single step. In dual
channel mode you can program a constant frequency offset between
the two channels for the sweep.
The SynthHD signal generator will generate hops. The GUI allows the user to program
up to 100 arbitrary points with a frequency and amplitude in dBm. This table is stored
onboard in nonvolatile memory. Like the sweep mode the user can then have an offset
on the other RF channel, hop up the list, hop down the list, and work with the trigger input.
Additionally, the SynthHD signal generator will digitally modulate FM, AM, and pulse.
FM can be a typical sinusoidal signal, or it can also be a chirp. AM can also be the t
ypical sinusoid signal or it can be ramps. The modulations can be combined. Combining
a pulse and a chirp allows the user to set up a frequency modulated continuous wave
(FMCW) radar signal. You can even combine this with the sweep function. As an
electronic warfare example, you could sweep a pulsed waveform across a range
of frequencies. Rates can be very slow, or in the case of FM, up to 5 KHz. Of course,
all of these features can be saved to the device; it will begin sweeping on power up
without a PC connected!
Use the external Trigger connection to perform external modulation such as
FM, AM and Pulse. More details here!!!!

SynthHD and SynthHD Pro Software GUI


Thursday, March 16, 2017

Windfreak's SynthNV RF Generator - review by Kenneth Wyatt

Kenneth Wyatt - November 25, 2013: Every once in a while, I discover a product that is so incredible I wonder why it hasn’t been publicized more widely. This is the case with Windfreak Technologies $599 miniature RF generator, the model “SynthNV” (Figure 1). In case you’re wondering, their company is named after the owner’s sailboat!

Figure 1 - The Windfreak Technologies SynthNV RF generator weighs just a few ounces and easily fits in your hand.

For months, I’ve been seeking a small RF generator that could replace the 40-pound monster I keep under my workbench. What really caught my eye initially was that the generator could AM modulate the RF output - perfect for radiated immunity pre-compliance testing! In addition, it will pulse modulate the output - perfect for testing to the MIL-STD-461 and DO-160 standards. The RF output level is sufficient to drive a near field probe with enough field strength to investigate susceptibilities within a product’s internal circuitry. But wait, there’s more! Here’s rundown of the features of this palm-sized jewel. Some of these additional features will be reviewed in Part 2 of this series. • RF sweep generator (34.4 MHz to 4.4 GHz at up to +19 dBm output) • Network analyzer (34.4 MHz to 4.4 GHz) • VSWR analyzer (using external power coupler) • RF power meter (real time) The generator is USB powered and can run on most Windows operating systems, including Windows 8. It also includes an external power adapter input, so it can be programmed into a given state and then disconnected from the PC and run standalone as a local oscillator or RF generator. There is a port that can source or receive an external 10 MHz clock, as well as an RF input port for measuring power. This port is also used for the network analyzer function.

Figure 2 - The basic user interface for the generator is based on National Instruments Labview.

The well designed user interface (Figure 2) is based on National Instruments Labview and the provided software includes the runtime engine for those who don’t own the full Labview software. It installed and ran just fine on my Macbook Pro with Parallels 9 and Windows 8. There are several tabs along the left half of the panel. These select the major functions of the instrument controller. When in manual mode, the large knob tunes the frequency in preset steps of 1kHz, 10kHz, 100kHz, 1MHz, 10MHz and 100MHz. The user may also enter frequencies directly by typing in the data blocks or by using a keyboard control in place of the large knob. The nominal +19 dBm RF output power is controlled by the rightmost panel. There are two buttons controlling the preset output. The High Power button will switch between the default high power or when pressed decreases the overall power output by about 55 dB (Low Power). A second button turns the RF on/off. The slide control further adjusts the output power by up to 31.5 dB. Note that the power scale is “dB’ and not the actual output power in “dBm”. This can be confusing at first, because the natural inclination is to assume the scale corresponds to the actual power output. This requires some mental calculations (or confirmation measurement) to set the precise output level. I suspect one slick way to confirm the desired power level is to run the output (through attenuators) to the “RFin” port to make that measurement. One improvement might be to redesign the slider to conform to the actual output power level - changing the scale according to the three preset power levels.

In stock at Saelig Co. Inc here!

Wednesday, March 15, 2017

Identify Machine Problems Before They Happen

Effective non-contact torque monitoring can help production quality as well as identify machine problems before they happen.

The importance of torque measurement in manufacturing environments is a new concept to some, but an everyday essential to others. Realizing the enormous cost benefits of measuring torque in rotating systems is sometimes not recognized by those tasked with improving profitability. The challenge is to be able to monitor and measure torque as accurately, unobtrusively, and economically as possible. For continuous-manufacturing processes where machines are driven by rotating shafts, machinery failure and subsequent downtime must be avoided in order to maintain profitability as well as consistency of output. The effective use of precision non-contact torque monitoring instrumentation can preemptively identify problems that might affect machinery reliability—extremely important for situations where a single machine failure can lead to costly production losses.

Read more here:

Tuesday, March 14, 2017

What are the key benefits of using ABI's PCB testers?

ABI customers save money repairing complex others said were impossible to .

Customers around the world are enjoying reduced time to fix boards, which produces savings in operating costs and equipment downtime.