|
 The
bridged-T filter is a quick-and-dirty construct used to notch out a specific
frequency that is interfering with a desirable frequency or band of frequencies.
It is a resonant LC (inductor-capacitor) circuit consisting of a single inductor
"bridging" a pair of series capacitors having a resistor to ground between them,
or, if preferred, a capacitor bridging one or two inductors. A convenient
nomogram (aka nomograph) is provided by the author in this 1964
Radio-Electronics magazine article for quickly selecting values, which was
a very popular design aid in the pre-calculator era. A slide rule could be used
to calculate a range of values when only a single variable was in play, but
juggling more than one variable (component value) was greatly aided by a
multivariable nomograph. Truth is nomographs can still...
 Television, in 1955, was still a relatively
new phenomenon to many - maybe even most - people. According to multiple sources,
the portion of American households with a TV set went from under 20% in 1950 to
nearly 90% ten years later in 1960. That was a meteoric rise, particularly considering
the expense of even a minimal TV. The technology was not even available commercially
when most people were born, so the rush to join in on the craze was akin to the
mass adoption of cellphones in the 1990s. "Carl &
Jerry" creator John Frye used his pair of electronics-savvy teenagers to help
make the "magic" behind recreating a moving picture on a CRT miles away from where
it was created. Water flowing through a garden hose has often been employed as an
analogy for current flowing through a wire to explain electricity to laymen and
beginning students of the craft. Here, it is not water flowing through the hose
but water leaving the hose and flowing through the air that serves to represent
an electron stream travelling from the electron gun to the phosphor-coated glass
front of a CRT. Frame rates, scan lines, deflection coils, and other relevant terms
are i
 "The
RF front-end (RFFE) industry, valued at $21 billion, is expanding beyond its
traditional focus on mobile and infrastructure to drive innovation in the automotive
sector. Each segment within the industry presents unique dynamics and growth opportunities.
After a difficult 2022, the smartphone market is showing signs of recovery, with
expected year-over-year growth of 4%, projected to reach 1.2 billion units by 2024.
The mobile RFFE market is predicted to hit US$18 billion by the end of 2024, though
it may face stagnation due to market saturation and pricing pressures. This
market is expected to expand, with the 2027 launch of RedCap..."
 I'm having a hard time writing this with
my eyes rolled back in my head. The last time I experienced this level of overwhelmedness
was probably the third or fourth week of my feedback and control class at UVM. Even
though
electricity and magnetism shares many complimentary and parallel concepts, for
some reason thinking in terms of magnetics when describing amplifiers, mixers, modulators,
etc., has always caused brain freeze. Maybe it has to do with an ingrained bias
due to my earliest dealings with circuits being from a technician background before
earning an engineering degree. The equations of electric fields and magnetic fields
are very similar so that helps lower...
 Temwell is a manufacturer of
5G wireless communications filters for aerospace, satellite communication, AIoT,
5G networking, IoV, drone, mining transmission, IoT, medical, military, laboratory,
transportation, energy, broadcasting (CATV), and etc. An RF helical bandpass specialist
since 1994, we have posted >5,000 completed spec sheets online for all kinds
of RF filters including helical, cavity, LC, and SMD. Standard highpass, lowpass,
bandpass, and bandstop, as well as duplexer/diplexer, multiplexer. Also RF combiners,
splitters, power dividers, attenuators, circulators, couplers, PA, LNA, and obsolete
coil & inductor solutions.
 Here we are with another set of three "What's
Your EQ?" circuit challenges, these from the February 1962 issue of Radio-Electronics
magazine. As usual, those challenges provided by Jack Darr are the purview of television
servicemen of the era. The photo shown of the problematic CRT display looks like
a chest x-ray or maybe hieroglyphics in the dark corner of a cave, but evidently
the artifacts are readily identifiable to an initiated few. The Forbidden Current
Path circuit answer is not what I thought it would be. I maintain that whether my
answer or the designer's answer is correct depends on the physical...
 "A new
world record
in wireless transmission, promising faster and more reliable wireless communications,
has been set by researchers from UCL. The team successfully sent data over the air
at a speed of 938 Gb/s over a record frequency range of 5–150 GHz. This speed
is up to 9,380 times faster than the best average 5G download speed in the UK, which
is currently 100 Mb/s or over. The total bandwidth of 145 GHz is more
than five times higher than the previous wireless transmission world record. Typically,
wireless networks transmit information using radio waves over a narrow range of
frequencies..."
 Sputnik refers to the first series of satellites
launched by the Soviet Union. The word "Sputnik" means "satellite" in Russian. The
launch of Sputnik 1 on October 4, 1957, marked a monumental moment in human history,
heralding the dawn of the Space Age and sparking a fierce technological competition
known as the Space Race between the United States and the Soviet Union. This satellite,
the world's first artificial one, orbited Earth at an altitude of roughly 215 to
939 kilometers and broadcast a radio signal that astonished the world, particularly
in the United States, where it spurred rapid advancements in aerospace and scientific
research. The successful launch of Sputnik was an achievement that was years in
the making, involving a combination of visionary planning, political motives, and
intensive engineering by some of the Soviet Union's top scientists.
Blog: Air Quality
Measurements with Particle Counters
 Transcat | Axiom Test Equipment, an electronic
test equipment rental and sales company has published a new blog post entitled "Provide
Essential Air Quality Measurements with These Particle Counters" that covers
how particle counters can provide essential measurement capabilities that can help
avoid contamination and support high manufacturing yields. These measurement tools
can detect and measure microscopic particles suspended in air that can contaminate
the most carefully planned manufacturing lines. Air particle counters can be designed
for various...
 In 1958, most people were not accustomed
to seeing the now-familiar maps plotting
sinusoidal
courses of satellites across the face of the earth. It had only been in October
of the previous year that any object other than the moon was in orbit around our
home planet - that was U.S.S.R.'s Sputnik. Just as people of all ages and all backgrounds
enthusiastically joined in the newfangled phenomenon of aeroplanes after the Wright
Brothers flew their fragile craft at Kitty Hawk, electronics communications and
scientists worldwide hopped aboard the satellite train. This article from a 1958
issue of Radio & TV News magazine provided insight into the construction
and flight characteristics...
 LadyBug Technologies was founded in 2004
by two microwave engineers with a passion for quality microwave test instrumentation.
Our employees offer many years experience in the design and manufacture of the worlds
best vector network analyzers, spectrum analyzers, power meters and associated components.
The management team has additional experience in optical power testing, military
radar and a variety of programming environments including LabVIEW, VEE and other
languages often used in programmatic systems. Extensive experience in a broad spectrum
of demanding measurement applications. You can be assured that our Power Sensors
are designed, built, tested and calibrated without compromise.
 What were some of the
top issues of the radio and television industry half a century ago? In a lot
of respects, the same things that concern it today. A ready supply of service technicians
was a concern that was taken seriously by the Electronics Industry Association (EIA).
While there are not many local repair shops for electronics products nowadays, there
is still a huge demand to techs who are willing and able to do the hard work of
keeping the world's communication infrastructure operational - climbing towers,
repairing cell equipment. Now, as then, good pay, job security, benefits, and respect
for the job being done were at the top of...
 In a parallel to the traditional test setup
of signal generation and signal acquisition, RIGOL Technologies announced today
the latest additions to its portfolio of
performance measurement equipment with the introduction of the DG5000 Pro Series
Generators and DHO/MHO5000 Series Oscilloscopes. The DHO/MHO5000 Series bring next-level
performance to RIGOL's respected line of high-resolution oscilloscopes, while the
DG5000 Pro generators do the same for the company's capable Pro Series arbitrary
waveform generators...
 When selecting articles for posting here
on RF Cafe, I like to include ones that are directed toward newcomers to the field
of electronics as well as for seasoned veterans. This piece from a 1958 issue of
Radio & TV News magazine entitled "Basic Electronic Counting," is a
prime example in that it introduces the concept of binary numbers. We've all been
there at some point in our careers. A big difference between now and when this article
appeared is that in 1958, almost nobody was familiar to binary numbers, and fuggetabout
[sic] octal and hexadecimal. Only those relatively few people designing and working
with multimillion dollar, vacuum tube-based digital computers installed in universities,
megacorporations, and government research facilities had ever dealt with digital
numbers. The earliest example of powers of two I remember was back in junior high
school. It had to do with a
 "Every invention begins with a problem -
and the creative act of seeing a problem where others might just see unchangeable
reality. For one 5-year-old, the problem was simple: She liked to have her tummy
rubbed as she fell asleep. But her mom, exhausted from working two jobs, often fell
asleep herself while putting her daughter to bed. 'So [the girl] invented a teddy
bear that would rub her belly for her,' explains Stephanie Couch, executive director
of the Lemelson MIT Program. Its mission is to nurture the
next generation of inventors
and entrepreneurs. Anyone can learn to be an inventor, Couch says, given the right
resources and encouragement. 'Invention doesn't come from some innate genius, it's
not something that only really..."
 Mechanical filters of the type described
in this 1969 Electronics World magazine article are yet another example
of the genius of some people. They are actually a form of electromechanical device
in that the applied electrical signals are first converted into mechanical signals,
followed by resonant mechanical elements that discriminate according to frequency,
and finally a conversion back to an electrical signal is made. It is fundamentally
the same principal as a crystal, SAW, or BAW filter, albeit each with distinctly
different methods and topologies. Mr. Donovan Southworth, of Collins Radio, presents
the basics of mechanical filters in this brief write-up...
LadyBug Technologies was founded in 2004
by two microwave engineers with a passion for quality microwave test instrumentation.
Our employees offer many years experience in the design and manufacture of the worlds
best vector network analyzers, spectrum analyzers, power meters and associated components.
The management team has additional experience in optical power testing, military
radar and a variety of programming environments including LabVIEW, VEE and other
languages often used in programmatic systems. Extensive experience in a broad spectrum
of demanding measurement applications. You can be assured that our Power Sensors
are designed, built, tested and calibrated without compromise.
 Attempts at making an
electronically printed facsimile (fax) of an original document at a location
distant from the source have been around for quite a while. As mentioned by
Radio-Electronics magazine editor Hugo Gernsback in this article, Samuel Morse
had a crude working device for printing messages on paper even before his eponymously
named code of dots and dashes became famous in 1837. A couple decades earlier, a
fellow named John Redman Coxe, of Philadelphia, Pennsylvania, devised a method of
electronically printing images and text on paper using a conductive solution and
a direct current pile (aka battery). Dr. Coxe, a physician, is not a well-known
figure in the electronics world, but in his day...
 "Researchers have discovered how the 'edge
of chaos' can help electronic chips overcome signal losses, making chips simpler
and more efficient. By using a metallic wire on a semi-stable material, this method
allows for long metal lines to act like superconductors and amplify signals, potentially
transforming chip design by eliminating the need for transistor amplifiers and reducing
power usage. A stubbed toe immediately sends pain signals to the brain through several
meters of axons, which are composed of highly resistive fleshy material. These axons
operate using a principle known as the 'edge of chaos,' or semi-stability, enabling
the swift and precise transmission of information..."
 The January 1969 issue of Electronics
World magazine published an extensive list of
Japanese company trade names and their addresses. Many of them went out of business
or were bought by other corporations long ago, as occurs in all countries. "Aiwa"
is listed twice, but that might have been a legitimate duplication due to separate
locations (BTW, I owned an Aiwa stereo at one time). My first "real" cassette tape
deck was made by TEAC (founded in 1953 as the Tokyo Electro Acoustic Company) and
my first "real" stereo receiver was made by Sansui. I remember the line in "Back
to the Future 3" where Doc Brown, having time-travelled from 1955, makes a
disparaging remark about a circuit in the DeLorean failing because of it being labeled
"Made in Japan." Marty counters...
• ARRL Defends
902-928 MHz Amateur Radio Band
• FCC's
Auto Safety Spectrum Rules
• $5M in U.S.
Chips Act Money to Metrology Projects
• U.S. State Department Approves
Surveillance Radar System Sale to Romania
•
5G Americas ITU IMT-2030 Vision for 6G White Paper
 John Redman Coxe was a prominent American
physician, scientist, and innovator born on September 20, 1773, in Philadelphia.
Coxe's intellect and curiosity drove him toward an illustrious career in both medicine
and early scientific exploration, which included experimentation in electrochemistry.
He graduated with a degree in medicine in 1794, setting the course for his lifelong
journey into medicine and early scientific innovation. Coxe broadened his approach
to medicine and science, inspiring him to explore the convergence of scientific
methods and practical applications. John Redman Coxe is most remembered not only
for his contributions to medicine but also for his interest in experimental physics,
particularly in the field of electrochemistry...
 TotalTemp Technologies has more than 40
years of combined experience providing thermal platforms.
Thermal Platforms are
available to provide temperatures between -100°C and +200°C for cryogenic cooling,
recirculating & circulating coolers, temperature chambers and temperature controllers,
thermal range safety controllers, space simulation chambers, hybrid benchtop chambers,
custom systems and platforms. Manual and automated configurations for laboratory
and production environments. Please contact TotalTemp Technologies today to learn
how they can help your project.
 When I saw this 1966 Radio-Electronics
magazine article entitled, "Vibration
and Shock - Nature's Wrecking Crew," for some reason the first thing I thought
of was "The Wrecking Crew," that anonymously played the music for a huge number
of popular singers - mostly those without prominent bands of their own during the
1960s and 1970s rock-and-roll era. ...but I digress. My introduction to the potential
deleterious effects of vibration on electronics was in the 1970s, with airborne
receivers and servos in my radio controlled model airplanes. Even though they were
transistorized, vibration from glow fuel engines could wreak havoc with potentiometers
in servos and solder joints everywhere, including battery packs. I remember seeing
the control surfaces jitter...
 You don't see jobs advertisements like this
anymore. Here is an ad that appeared in the the July 1944 edition of QST
(the American Radio Relay League's, ARRL's, monthly magazine), placed by Raytheon
Manufacturing Company (now just Raytheon Company), looking for
vacuum tube design, test, and processing engineers. Licensed amateur radio operators
were in high demand during the war years because of their knowledge and enthusiasm
for electronics and wireless communications. I hope you didn't come to this page
hoping to really find a tube designer job available. Of course, there are still
vacuum tubes being designed for TWTs and magnetrons, but those are few and far between...
 The "carborundum"
signal detector, an innovative device developed by engineer General H. H. C. Dunwoody
in the early 20th century, represents a significant advancement in radio technology,
particularly in the context of crystal detectors used for receiving radio signals.
This device utilized the unique properties of silicon carbide, also known as carborundum,
which was synthesized in the late 19th century by Edward Goodrich Acheson. The connection
between Dunwoody and the material lies in the application of carborundum as a semiconductor
in radio signal detection. The operational theory of the carborundum signal detector
is rooted in its ability to rectify alternating current (AC) signals. When radio
waves, which are essentially electromagnetic waves...
 "Researchers have created a cutting-edge
structure by placing a very thin layer of a special insulating material between
two magnetic layers. This new combination acts as a quantum anomalous Hall insulator,
significantly broadening its potential use in developing ultra-efficient electronics
and innovative solar technology. A Monash University-led research team has found
that a structure featuring an ultra-thin topological insulator, sandwiched between
two 2D ferromagnetic insulators, transforms into a large-bandgap quantum anomalous
Hall insulator. This heterostructure opens the door to ultra-low energy electronics
and even topological photovoltaics..."
|
 "Tokyo is now a next-door neighbor-thanks
to the magic of short-waves." That statement was made in a 1935 edition of Short
Wave Craft magazine after the American Telephone and Telegraph (AT&T) company
completed its wireless phone (voice) link between the U.S. and Japan; which is the
first 'T' in AT&T. Most people today would probably have a hard time guessing
that the
second 'T' in AT&T stands for 'telegraph.' Its surprising that the name
has not been changed to reflect the outdated-ness. Western Union sent its final
telegraph in 2006. Another news headline a couple years ago reported on India sending
its final official telegraph message...
 It was a lot of work, but I finally finished
a version of the "RF &
Electronics Schematic & Block Diagram Symbols"" that works well with Microsoft
Office™ programs Word™, Excel™, and Power Point™. This is an equivalent of the extensive
set of amplifier, mixer, filter, switch, connector, waveguide, digital, analog,
antenna, and other commonly used symbols for system block diagrams and schematics
created for Visio™. Each of the 1,000+ symbols was exported individually from Visio
in the EMF file format, then imported into Word on a Drawing Canvas. The EMF format
allows an image to be scaled up or down without becoming pixelated, so all the shapes
can be resized in a document and still look good. The imported symbols can also
be UnGrouped into their original constituent parts for editing...
 As I have written often, Hugo Gernsback was
one of the electronics industry's most prolific authors, inventors, and innovators.
In this 1947 article in his Radio-Craft magazine, he proposes using
printed components in place of leaded resistors. In fact, he sold printed resistive
cards through his Radio Specialty Company (Rasco) that could be cut into whatever
size was needed to achieve the required amount resistance based on a certain ohms/square
value. He also mentions creating printed inductors on Bakelite and even fashioning
variable-coupling transformers with a pair of inductor plates sliding relative to
each other, similar to capacitive "variometers" used for tuning RF circuits. Not
to neglect the possibility of capacitors, Gernsback suggests possibly spraying a
thin conductive coating on paper and then rolling multiple layers into a tubular
form, achieving a smaller form factor per unit capacitance that what was currently
being achieved. Single- and double-sided printed circuit boards were already being
used for some high volume, compact portions of assemblies, and he proposes improving
methods to eventually...
 Popular comic strips (aka 'funnies') in
the 1930s and 1940s featured numbskulls, ne'er-do-wells, and simpletons. There was
usually one character in the strip's cast that was smart - at least in a relative
way if not absolute. Being familiar with some of the old comics like Blondie, Barney
Google, Krazy Kat, Beetle Bailey, Gasoline Alley, etc., I can see a definite relationship
between the story line of "Entertaining
Uncle Oscar" and the comics of the era in this short story that appeared in
a 1939 edition of the ARRL's QST magazine. As you might guess, the feller
named 'Ham' is the smart one. Q: Is it irony, coincidence, or premonition on the
author's part that the uncle's name is the same as the ARRL's OSCAR series of Orbiting
Satellite Carrying Amateur Radio(s)?
 This is a really nice
electronic schematic symbols chart that will come in handy for hobbyists who
work with vintage electronic equipment. Not only does it have component symbols
that a modern chart (this appeared in a 1942 issue of Radio-Craft magazine)
would not likely contain, but it has three-dimensional sketches of each device.
For example, vacuum tube symbols show the tube outline, its socket configuration,
and the pinout. If you get nostalgic for some of these old parts, some of them like
the knife blade switch and ceramic light socket can be bought a many hardware stores
or online. It's too bad the chart is not in color because it would make a nice picture
to frame for a decoration. If anyone with an artistic bent feels compelled to colorize
it and send it to me, I'll be glad to make it available to visitors...
 The Remington Rand "Univac" (UNIVersal
Automatic Computer) computer was delivered on March 31, 1951.
Its main memory consisted of liquid mercury delay lines arranged in 1000 words of
12 alphanumeric characters each. A Univac famously calculated the first presidential
race forecast - Eisenhower vs. Stevenson - and was correct! This 1957 report in
Radio & Television News magazine mentions how "giant electronic computers
no longer rank as laboratory curiosities or frightening science-fiction robots."
The Unisys company is today's descendant of Remington Rand...
 The discussion of waveguides, up to this
point, has been concerned only with the transfer of energy from one point to another.
Many waveguide devices have been developed, however, that modify the energy in some
fashion during transit. Some devices do nothing more than change the direction of
the energy. Others have been designed to change the basic characteristics or power
level of the electromagnetic energy. This section will explain the basic operating
principles of some of the more common waveguide devices, such as
Directional Couplers, Cavity Resonators, and Hybrid Junctions. The directional
coupler is a device that provides a method of sampling energy from within a waveguide
for measurement or use in another circuit. Most couplers sample energy traveling
in one direction only. However, directional couplers can be constructed that sample
energy in both directions...
RF Cascade Workbook is the next phase in the evolution of RF Cafe's long-running
series, RF Cascade Workbook. Chances are you have never used a spreadsheet
quite like this (click
here for screen capture). It is a full-featured RF system cascade parameter
and frequency planner that includes filters and mixers for a mere $45. Built in
MS Excel, using RF Cascade Workbook is a cinch and the format
is entirely customizable. It is significantly easier and faster than using a multi-thousand
dollar simulator when a high level system analysis is all that is needed...
 Tracking down the source of TVI (television
interference) or any kind of RFI (radio frequency interference) can be a challenge. In the days
when most people received their audio and visual entertainment (radio and TV) via
over-the-air broadcasts, any form of interference was usually picked up by multiple
people, who promptly reported the issue to the power company or the FCC. Arcing
power lines, transformers, and switches were prime generators of RFI, particularly
during wet and high wind conditions. However, much more prevalent was interference
from industrial and domestic equipment. Neon and fluorescent light, heating pads
(see Hazel: Stop Rockin' Our Reception episode), ignition systems (automotive and
oil burners), diathermy (heat therapy popular in the day), industrial RF heating,
kitchen appliances, and tool motors were among the likeliest offenders. Of course
amateur radio operators were guilty of spewing out interfering EM crap...
 Westinghouse is yet another of the original
stalwart titans of companies that helped build America to her state of greatness,
but is now mostly a footnote in the historical notes of the many companies which
over the past few decades have bought out portions of the business. Founded in the
late 1800s by George Westinghouse as a locomotive air brake manufacturer, the company
added other markets including, notably, electric power generation and distribution.
Emerging as the winner in the famous "War of the Currents" fought between Westinghouse
and Thomas Edison secured George's place in history. Westinghouse also got into
the commercial, military, and domestic electronics and appliance markets. I worked
at the Westinghouse Oceanic Division in Annapolis, MD, from 1982 through 1986 and
though it was a great company to work for. This advertisement for "Westinghouse
Directional Equipment;" i.e., antennas, appeared in a 1945 issue of Radio News
magazine.
 The manned space program has unarguably provided
mankind with many new and innovative tools, medicines, electronics, materials, physics,
materials, appliances, and mathematics. Known officially as "spinoffs," products
include items like the portable heart defibrillator unit, the portable vacuum cleaner,
freeze-drying food processors, powdered lubricants, memory foam, quartz clocks and
battery-powered tools. Many
NASA inventions have not found an application in your basement
or garage, however, because their purpose is too specialized. Take, for instance,
the ZeRT, or Zero Reaction Tool...
 Voltage multipliers were found in nearly
every form of battery-powered electronics in the days of vacuum tubes, because of
the 100-volt or more requirement for plate voltages. Primary batteries in 30, 45,
and 67½ volt sizes were produced by Eveready, Burgess, and a few other companies
in order to help simplify biasing circuits. They were bulky and heavy, often comprising
a significant portion of the assembly's volume. Heavy transformers contributed mightily
to the weight and size as well. Exell still manufactures 30, 45, and 67½ V
batteries both for the few products that are still designed to use them, and for
vintage radio owners. Most circuits that need higher DC voltages these days use
DC-DC converters, many of which are ICs...
 OK, class, put your books away and take out
a pencil. Spread your chairs out because we're going to have a short test today.
A collective sigh permeates the room. Remember those days? I still have nightmares
over those moments, and they were decades ago for me. At least this "Electronic
Noise Quiz" from the August 1962 edition of Popular Electronics
won't affect your GPA. Sometimes PE's quiz illustrations are kind of hard to
interpret, but this one does a pretty good job (except item 'E', but I'm not
telling what it is since nobody helped me). You will need a fairly diverse
background in consumer type electronics to do well, and having a few gray hairs
will probably help as well. Good luck. BTW, my score was a somewhat embarrassing
80%...
 This
Technology Theme Crossword Puzzle for June 27th has many words and clues related
to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics,
and other technical subjects. As always, this crossword contains no names of politicians,
mountain ranges, exotic foods or plants, movie stars, or anything of the sort unless
it/he/she is related to this puzzle's technology theme (e.g., Reginald Denny or
the Tunguska event in Siberia). The technically inclined cruciverbalists amongst
us will appreciate the effort. Enjoy!
One of the perks of attending the International Microwave Symposium (IMS), hosted
by the Institute of Electrical and Electronics Engineers (IEEE), is that you are
given the opportunity to see a part of the history of microwave engineering. At
the two IMS shows that Melanie and I have been to (2009 and 2011), a portion of
the contents of the
National Electronics Museum, headquartered in Linthicum, Maryland,
(only a few miles from the Baltimore Convention Center) was on display. Safely locked
behind protective glass and guarded by a paid sentinel are relics of our profession's
past. Prototypes of magnetrons, circulators, filters, phased array antennas, traveling
wave tubes, waveguide, oscillators, and a host of other devices dreamed up ...
 There is no such thing as too many introductory
articles on
operational amplifiers (opamps). Of course, when this story was
written for Electronics World back in 1967, opamps were relatively new to the scene.
Prior to the advent of opamps, circuit design for controllers, filter, comparators,
isolators, and just plain old amplification was much more involved. Opamps suddenly
allowed designers to not worry as much about biasing, variations in power supply
voltages, and other annoyances, and instead focus on function. Even from the very
beginning with the μa741 operational amplifier, the parameters came close to those
of an ideal device: infinite input impedance, zero output impedance, perfect isolation
between ports, and infinite bandwidth. OK, the bandwidth spec was more constrained
compared to the other three, but still, with frequencies...
 This
Science Celebrity themed crossword puzzle for December 12th contains no
fewer than 18 names of notable scientists and engineers (marked with an asterisk
*) known famously to folks like you who visit RF Cafe. It took quite a while
to design. Elsewise, only clues and words which are directly to RF, microwave, and
wireless engineering, optics, mathematics, chemistry, physics, and other science
subjects. As always, this crossword contains no names of politicians, mountain ranges,
exotic foods or plants, movie stars, or anything of the sort unless it/he/she is
related to this puzzle's technology theme (e.g., Reginald Denny or the Tunguska
event in Siberia). The technically inclined cruciverbalists amongst us will appreciate
the effort...
 With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils
available for RF, analog, and digital system and schematic drawings! Every stencil
symbol has been built to fit proportionally on the included A-, B-, and C-size drawing
page templates (or use your own page if preferred). Components are provided for
system block diagrams, conceptual drawings, schematics, test equipment, racks, and
more. Page templates are provided with a preset scale (changeable) for a good presentation
that can incorporate all provided symbols...
 In 1957, only a top-of-the-line automobile
deserved a radio containing 13 discrete transistors and four crystal diodes. Only
buyers of such a top-of-the-line vehicle could afford the luxury offered by an electronic
marvel that promised instant-on music with superior sensitivity and selectivity
over the vacuum tube models that lesser humans endured. As shown in this 1957 issue
of Radio & TV News magazine,
Delco's Model 7268085 was up to the task as it populated the dashboards of Cadillac's
Eldorado Brougham. Modern day radios use a single IC for performing all reception,
filtering, amplification, and tuning functions, with superior performance compared
to the Delco without all the interstage tuning transformers, Rs, Ls, and Cs. Most
of the rest of the circuitry in your car radio is for microprocessor control...
 This Radio-Craft magazine article
starts out stating, "A skilled mathematician with a desk calculator requires four
years to do what the
IBM Calculator does in eight hours." That was in 1948. Just last
month a headline read, "Given the task of finding a pattern in a seemingly random
series of numbers, Google's quantum computer produced an answer in 3 minutes and
20 seconds. It estimates that the Summit supercomputer here at the Oak Ridge National
Laboratory in Tennessee would take 10,000 years to complete the task. The IBM 12,000
vacuum tube computer performed its calculation for an improvement factor of [(3 yr
• 8760 hr/yr) + (1 yr • 8784 hr/yr)] ÷ 8 hr = 4383 (4.383
thousand). The Google quantum computer performed its calculation for an improvement
factor of (10,000 yr • 31557600 s/yr) ÷ 200 s = 3.15776E11 s ÷ 200 s =
1.57788E9 (1.57788 billion -- or milliard)... |
