RF - VHF and UHF amplifier handbook

Started by jozamm in sci.electronics.design8 years ago 12 replies

Hi all, I am looking for a book that covers amplifiers and radio reception in the VHF and UHF range in a practical manner. I am learning on...

Hi all, I am looking for a book that covers amplifiers and radio reception in the VHF and UHF range in a practical manner. I am learning on this subject so if I have some circuits/projects which I can build and test would be very helpful for me. If it is a book specializing in RF amplifiers and low noise amplifiers the better. Thanks, jozamm


Any experience with negative impedance?

Started by Adrian Tuddenham in sci.electronics.design9 years ago 183 replies

The requirement is to design a specialist one-off audio amplifier to drive a loudspeaker at the end of a long cable for experimental purposes. ...

The requirement is to design a specialist one-off audio amplifier to drive a loudspeaker at the end of a long cable for experimental purposes. The voice coil is nominally 15 ohms with a pure resistance of 10 ohms. The loop resistance of the cable will be somewhere between 2 and 4 ohms. It would be desirable to have a damping factor of 10 or better, so I need to reduce the effect of the cab...


Looking for fast-ish sot-89 NPN

Started by Gerhard Hoffmann in sci.electronics.design3 days ago 7 replies

Hi, I'm trying to build a 2-200 MHz isolation amplifier. For 13 dBm I need abt. 120 mA peak current, 70 mA quiescent. The circuit is a...

Hi, I'm trying to build a 2-200 MHz isolation amplifier. For 13 dBm I need abt. 120 mA peak current, 70 mA quiescent. The circuit is a voltage to current converter, followed by a double cascode. 2N3904 is too slow, BFQ19S is too hot, it would do 1 GHz, but brings me negative input impedance, gain peaks and so on. I'm playing with the usual ferrite beads, but that does not bring com...


IF AMPLIFIER IN RADIO RECIEVER

Started by RealInfo in sci.electronics.design9 years ago 20 replies

Hi all What is the "right" total amplification factor of an IF amplifiers chain in a radio receiver ? For example a receiver employs 4 IF...

Hi all What is the "right" total amplification factor of an IF amplifiers chain in a radio receiver ? For example a receiver employs 4 IF amps cascade , what is the proper total voltage amplification of that IF cascade ? Thanks in advance EC


Mixing 4 audio channels to 3?

Started by DaveC in sci.electronics.design10 years ago 93 replies

I want to connect the audio out (headphone jack) of 2 computer sound cards to a desktop & woofer speaker-amp combination. (The original input...

I want to connect the audio out (headphone jack) of 2 computer sound cards to a desktop & woofer speaker-amp combination. (The original input was via USB only and I'm modifying this for analog audio input.) This is my guess at the necessary resistors to mix down these 4 outputs to the 3 inputs in the amplifier (L, R, sub): The data sheet for the P


Wide Area Loop Coil Design

Started by Anonymous in sci.electronics.design7 years ago 42 replies

I would like to make a wide area circular loop of approximately 3 metres diameter. It will be fed with audio sinewaves via a 100W (per...

I would like to make a wide area circular loop of approximately 3 metres diameter. It will be fed with audio sinewaves via a 100W (per channel) car stereo amplifier. Could I please have some suggestions on: 1. The best way to construct this so it would be moveable. I also need it to function as a former into which to loose wind the coil. 2. Given the continuous signal, a suitable ...


Photodiode bootstrap phase rolloff

Started by David Nadlinger in sci.electronics.design5 years ago 16 replies

Hi all, I am currently working on a range-switched photodiode design for use in our laboratory [1]. It took me a while, but I've arrived at a...

Hi all, I am currently working on a range-switched photodiode design for use in our laboratory [1]. It took me a while, but I've arrived at a design I'm fairly happy with (in no small part thanks to Phil Hobbs' helpful writings on the topic): My current draft uses a simple BF862 source follower at the summing node of a ADA4817-based 2 M?/2 k? transimpedance amplifier to bootstrap t


Watch finder

Started by Liz Tuddenham in sci.electronics.design8 months ago 22 replies

A long time ago I made a cable tracer from a coil of 2,000 turns of wire on an old solder spool, connected to a high gain amplifier that...

A long time ago I made a cable tracer from a coil of 2,000 turns of wire on an old solder spool, connected to a high gain amplifier that fed headphones. After using it for the job that needed it at the time, I put it away in a box "just in case". Today I realised that my watch was no longer on my wrist although I remembered putting it on this morning; a thorough visual inspection of the h...


HP5316 1GHz counter front end

Started by Anonymous in sci.electronics.design6 years ago 2 replies

I got a 5316 counter off ebay with OCXO and 1GHz channel. There's a differential amplifier/receiver in there, HP pn 1826-0589. Of course, the...

I got a 5316 counter off ebay with OCXO and 1GHz channel. There's a differential amplifier/receiver in there, HP pn 1826-0589. Of course, the x-ref lists I've found so far jump from 1826-0588 to 1826-0590. Either of those parts have nothing to do with amplifying. Anybody have a clue what this part could be? The BOM claims it's a TO-8, but the schematic shows 12 pin numbers... I'll take t...


Request for circuit analysis

Started by rajibbandopadhyay in sci.electronics.design10 years ago 18 replies

Dear friends, The reason why I got stuck with electronic circuits just before biasing will be clear in a short while. Without the support of a...

Dear friends, The reason why I got stuck with electronic circuits just before biasing will be clear in a short while. Without the support of a good teacher the logic involved appears formidable. The pages attached relate to transistor as an amplifier and its biasing. The book concerned is All.new.electronics.self-teaching.guide.2008. The questions are posted on some of the attached pages...


BJT biasing

Started by riccardo manfrin in sci.electronics.design9 years ago 19 replies

With reference to this network (of common emitter...

With reference to this network (of common emitter amplifier) http://4.bp.blogspot.com/_Dw6bXh3FG1Q/R61fbJKINdI/AAAAAAAAAOc/Ae6ExBcFSdI/s320/CE.GIF I'm trying to bias the BJT through the two tunable parameters - base resistance R_b - collector resistance R_c R_c should be chosen - small enough to admit the amplification of the whole input signal dynamic (without entering saturation n...


Urgent advice needed! Build a two-way crossover for speaker

Started by Anonymous in sci.electronics.design7 years ago 2 replies

Hi all. I am a DJ and I use two active 12" speakers for tops. Today one of them broke and I have a gig on Saturday. I have an amplifier rig...

Hi all. I am a DJ and I use two active 12" speakers for tops. Today one of them broke and I have a gig on Saturday. I have an amplifier rig with lots of free channels and want to convert those active tops to passive with a simple built in crossover. I know it's not according to "the book" but I have tried just to add a MKP cap of 8uF in series with the tweeter and it sounds good. The inpu...


Cascode substitutions

Started by Tim Williams in sci.electronics.design6 years ago 76 replies

Designing an RF amplifier. Concept is, high power, complementary cascodes for the output stage (with heavy class A use, but being PP, class AB...

Designing an RF amplifier. Concept is, high power, complementary cascodes for the output stage (with heavy class A use, but being PP, class AB is an option). 50 ohm output, direct drive, say 10W level. I happen to have a complementary pair that's not too slow (2SC2690A and 2SA1220A), and I'd like to maximize the bandwidth around that. The NPN side is fine, I have a 30V, 1A, 2GHz tran...


OT: Electronic Design!

Started by Cursitor Doom in sci.electronics.design3 years ago 20 replies

In a surprise change from the usual topics discussed in this group, I'm posting a question about electronic design! Win kindly reposted this...

In a surprise change from the usual topics discussed in this group, I'm posting a question about electronic design! Win kindly reposted this enhanced schematic of an amplifier board I've been troubleshooting:- https://www.dropbox.com/s/o4tybr81cefbk5n/8565A_amp.GIF?dl=1 My question relates to the voltage-to-current section which comprises 6 transistors plus various passive 'support'...


Ft doubler

Started by Jeroen Belleman in sci.electronics.design2 years ago 5 replies

We had a rainy weekend here and I decided to spend some time simulating Battjes' Ft doubler and to compare it with a more ordinary differential...

We had a rainy weekend here and I decided to spend some time simulating Battjes' Ft doubler and to compare it with a more ordinary differential cascode amplifier with similar gain and bias conditions. I sort-of expected to find that the bandwidth of the Ft doubler would roughly be twice that of the simple differential stage, but I did not find that. In fact, the bandwidth is about the sam...


RIS-660A, my latest upgraded design

Started by Winfield Hill in sci.electronics.design5 years ago 14 replies

Segmented photodiodes are used for lightbeam position sensing. Generally you want to know relative light beam displacement, rather than...

Segmented photodiodes are used for lightbeam position sensing. Generally you want to know relative light beam displacement, rather than absolute light levels. We solve this with a normalizing amplifier, which can be made using a precision analog multiplier in divider mode. After many years of making complicated versions of this type of circuit (p/n RIS-270), in 2008 I designed...


Writing to MCU flash

Started by Phil Hobbs in sci.electronics.design3 years ago 108 replies

So we've got this custom product that includes a voltage-controlled amplifier. VCA chips as used in ultrasound and so on have nice low noise...

So we've got this custom product that includes a voltage-controlled amplifier. VCA chips as used in ultrasound and so on have nice low noise at the highest gains, but at low gain they stink on ice. The same is true of all transconductance-based VCAs unless you use a zillion stages. Sooo, we're faking it with a dpot, an op amp with a mux-controlled resistor ladder, and an LPC804 Cort...


Design Error 2 extra

Started by Phil Allison in sci.electronics.design3 years ago 6 replies

Hi to my tormenters, --------------------- the tube amp question left most of you a tad agog. Yet it was simply a case of noting that...

Hi to my tormenters, --------------------- the tube amp question left most of you a tad agog. Yet it was simply a case of noting that opening the s/b switch altered the topology of the amplifier in a not good way. Since transient over-voltage on the plates leading to insulation failure is a common thing with tube amps generally, many makers apply a simple fix using high voltage dio...


Noise and gain in transimpedance amplifiers

Started by Anonymous in sci.electronics.design6 years ago 34 replies

Hi, I have a few questions about gain and noise in the transimpedance amplifier. I've been mainly reading Hobbs (2nd edition) and H&H AoE (3rd...

Hi, I have a few questions about gain and noise in the transimpedance amplifier. I've been mainly reading Hobbs (2nd edition) and H&H AoE (3rd Ed). References below are to those editions. Most importantly, thank you to the authors for these wonderful texts! === Rolloff of transimpedance === Hobbs Eqn 18.10 gives an expression for the transimpedance Zm, and states t


Electrolytic Capacitor as Audio Test Load

Started by Steve Morris in sci.electronics.design4 years ago 17 replies

I was wondering what would happen if I wired the output of a 100W audio amplifier directly across a sizable (4700uF) electrolytic...

I was wondering what would happen if I wired the output of a 100W audio amplifier directly across a sizable (4700uF) electrolytic capacitor. It could be assumed the amp is push-pull and the cap is polarized. How would it react in terms of a test load? Steve Morris