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Morpheus: Let me tell you why you're here. You're here because you know something. What you know you can't explain, but you feel it. You've felt it your entire life, that there's something wrong with the world. You don't know what it is, but it's there, like a splinter in your mind, driving you mad.

Because the original files are large and slow to down load as .PDF files, I have converted them to fast to load DjVu format files. You need to get the DjVu plugin to view these files if you don't already have it.

Juerg Koegel, on the Time Nuts List sent along the paper,

Optimization Of Dual-Mixer Time-Difference Multiplier
[in PDF format ] {in OCRed DjVu format }

Lambda Diode [DjVu Format]:

If you want negative resistance, without using Tunnel Diode, you can use a NE-2/1A1 Neon Bulb if you can deal with the voltage, or a Lambda Diode.

The Lambda Diode is made from two back-to-back JFETs. The selection of the JFET part number controls voltage set point.

Date: Fri, 31 Jul 1998 01:46:11 -0800
From: "P. Faasse" >faasse@nlr.nl<
Subject: Re: Tunnel Diodes?

I have been looking for tunnel diodes too, some time ago. I have never been able to find any new ones. I did find some in a dusty cabinet. It turned out that one of our HP frequency counters had used them in it's input circuit. The frequency counters where long dead, so that's how I got some.

I did find out that it's not so difficult to make a quite similar device using two j-fets. This seems to be called a lambda-diode. The circuit goes as follows:

It's not exactly a tunnel diode, but works quite the same in the 'negative-impedance' region. Only the voltage level where that happens is a little higher than a normal tunnel diode (2.5 Volts with a 2N3819 and 2N3820 pair).

I've been playing with this contraption some time, even built a high-frequency oscillator with it (put it in series with an LC parallel circuit) works nicely up till the 400 MHz range. A series diode will help keep the thing from getting reverse-biased when you use a high-Q LC circuit. This thing is quite nice for getting low-power above-Vcc or below-Gnd voltages too, the lambda-diode, an LC-circuit and a diode/capacitor will work nicely. The lambda-diode and LC circuit will swing, the LC voltage will go above/below the supply rail voltage and the diode/capacitor will rectify/keep the voltage.

The most dramatic thing I've ever done with this circuit is blow the input circuit of a frequency counter. I was testing what the frequency range of this thing was. I was not monitoring the oscillator voltage however. At one time the oscillator voltage went up to way beyond the permitted input voltage of the frequency counter, and the holy smoke escaped from it. It turned out that I had managed to produce more than 250 Volts peak voltages from a 5-volts-supplied LC oscillator.

greetings,

Peter Faasse

--------------------------------------------------------------------

The Negistor & Negative Resistance - 04/07/00 courtesy Marcelo Puhl - From Keelynet.

Synchronous oscillator outperforms the PLL [DjVu Format]:   The PLL has numerous limitations, including low input-signal sensitivity and contradictory design requirements. The synchronous oscillator doesn't suffer from these problems and has many powerful properties, including three internal filters and a self-regulation property. - EDN November 11, 1999.

United States Patent, in DjVu format: 4274067, 4335404, 4356456, 6667666.

Synchronous oscillator converts audio, video to FM: The synchronous oscillator (SO) and the coherent phase-locked synchronous oscillator (CPSO) are universal multifunctional networks that track, synchronize, and amplify as much as 80 dB; improve SNR by as much as 70 dB; and modulate AM, FM, and FSK signals. You can also use these networks as ADCs, sampling networks, and dividers that divide by rational integer numbers, such as 3/4, 5/7, and 7/8. Suitable applications include wideband spread-spectrum communications and binary-phase-shift-keying (BPSK) and quadrature-phase-shift-keying (QPSK) generation. A CPSO retains all the properties of the SO and provides zero phase error. Vasil Uzunoglu, Synchtrack, Gaithersburg, MD -- EDN, 7/22/1999

Voice Link Over Spread Spectrum Radio - Introduction [See part two for Synchronous oscillator usage]. This is originally from TAPR Spread Spectrum Pages but their JavaScript makes the pages impossible to see in most modern browsers.

A couple of sections from the GE SCR Manual, mostly the section on Phase Control. Some day I hope to get it all scanned but this takes a lot of time. A few bucks might speed up the process if you need it faster. :-)

How to use Input Capture to do period measurements. Code is based on the old 6801, but the concepts apply to all of the newer parts as well. It covers the "gotcha's" new embedded programmers have not been bitten by yet.

Data sheet for ER3400 in DjVu Format, about 500K. The ER3400 is one of the first EEPROMs that there was, you find it some old equipment. Myself I'd replace the thing with a Atmel AVR processor. The AVR is fast enough to simulate this chip.

Data sheet for MC3344 in DjVu Format, about 100K. This is a integrator based "Tone Decoder". Higher frequencies charge up a cap faster than slower frequencies.

Cure for Test Anxiety.

Richard Hull's Electrometer.

Fast Ancient Multiplication Method.

Flex Your Design Muscles.

Light Noise Cancellation via Transimpedance Amp/ground base 2N3904..

PERT Schedules.

Simple Phase Meter Operates To 10 MHz.

Variable Duty Cycle Algorithm.

From Analog Devices:

An IC Amplifier Users Guide to Decoupling, Grounding,and Making Things Go Right for a change.

Technical Support Application Guides

Application Notes

From Atmel:

AVR040: EMC Design Considerations This Application Note covers the most common EMC problems designers encounter when using Microcontrollers.

From Motorola:

Engineering Bulletins:
EB349/D RAM Data Retention Considerations for Motorola Microcontrollers.
EB398/D Techniques to Protect MCU Applications Against Malfunction Due to Code Run-Away.

AN1051: Transmission Line Effects in PCB Applications.

As rise and fall times become faster in order to achieve high operating speeds, transmission line effects on PCBs can be very significant, with the possibility of unpredictable behavior. This note presents a guideline when to analyze, discusses the characteristics of different types of PCB trace, describes Lattice Diagram and Bergeron Plot analysis, and summarizes termination methods. Includes 10 worked examples.

AN1061: Reflecting on Transmission Line Effects.
AN1259/D System Design and Layout Techniques for Noise Reduction in MCU-Based Systems.
AN1263/D Designing for Electromagnetic Compatibility with Single- Chip Microcontrollers.
AN1705/D Noise Reduction Techniques for Microcontroller-Based Systems.
AN1744/D Resetting Microcontrollers During Power Transitions.
AN2321/D Designing for Board Level Electromagnetic Compatibility.

From TI:

Operational amplifiers (op amps) and comparators look similar; they even have very similar schematic symbols. This leads a lot of designers to think they are interchangeable. There is a strong temptation to use a spare section of a multiple op amp package as a comparator to save money. This application note will explain why designers should not do this.

Download .pdf (sloa067.pdf, 150 Kbytes)

Analog Devices gives simular advice in their Seminar Application Manuals.

From Zilog:

Minimizing EMI Effects During PCB Layout of Z8/Z8Plus Circuits.
Using Software Techniques to Maximize Z8 MCU System Noise Immunity.

If you are designing any system with blinking lights or LEDs then keep Photosensitive Epilepsy in mind.

These quotes come from the website of the British Epilepsy Association:

http://www.epilepsy.org.uk/info/photofrm.html:
- "It should be bore in mind that people with photosensitive epilepsy are unlikely to be troubled by a flicker rate of under five per second"
- "Only 50% of photosensitive people are sensitive to 50Hz but 75% are sensitive to 25Hz"
- "100Hz television sets will almost entirely solve the problem"

This quote comes from the website of the National Society for Epilepsy (UK):

http://www.epilepsynse.org.uk/pages/info/leaflets/photo.cfm:
- "The frequency of flashing light which is most likely to provoke seizures varies from person to person. Generally, it is between the frequencies of 5-30 flashes per second (hertz). Some people, however, are photosensitive at higher flash frequencies. It is uncommon to have photo-sensitivity below 5 hertz."

Avoid LED blinking or modulation at rates between 5 and 100Hz.

If hyperspace navigators get paid by the hour, then what is the pay-scale in a place where time has no meaning?

(FROM THE US NAVAL OBSERVATORY)