RF Radio Frequency Receiver Circuits   Page 2
RF Receivers:  #-B      C-Q      R-Z
Last Updated on: Wednesday, December 31, 2008 03:17 PM
 

Car Radio tunes the Amateur Bands:  (added 2/05)

Circuit Detects Current Pulses:  01/06/94 EDN-Design Ideas / (Electronic Circuit diagram added 03/03)  The pulse detector provides a visible indication of positive and negative current pulses. The pulses amplitudes can vary from20 to150 mA. The pulses durations can range from10 to40 msec, and their repetition rate can span40 to180 pulses/minute.

Compact L Match ATU for Portable use:  (added 2/05)

CompactPCI in Wireless Base Stations:  Agilent Application Note   (Circuit / schematic design added 6/06)

Constant-impedance IF bandpass filters improve circuit Performance:  Application Note - MiniCircuits.com  (Circuit / schematic design added 6/06)

Crystal Controlled Time Base Generator:  (Electronic Circuit / Schematic added 10/04)

Crystal Radio #1:  This is a generic circuit, the first true radio receiver in history. Description:  Crystal radio requires no power supply to operate because it uses energy from the signals it receives. Performance is - like one should expect - poor. Nevertheless, with a good antenna and proper ground, it shouldn't be too difficult to tune to a strong AM station.  While this circuit is very simple, many points should be observed. The variable capacitor is relatively hard to get in a store these days, so your best bet to find one could be a junked AM receiver. Connect the case to the antenna and the central rod to ground. Otherwise, you'll de-tune the circuit every time you touch the capacitor.….  (added 10/05)

Crystal Radio #2:  RF Receivers & Receiver Circuits Crystal Radio (Electronic circuit added 5/02)

Crystal Radio Circuits including Diode Performance Comparison:  (added 8/03)

Crystal radio with Amplifier:  An improved crystal radio with a two-stage audio amplifier. The 2N3904 (or any other general-purpose NPN) acts as a preamplifier while the LM386 boosts the signal high enough to drive low impedance Walkman headphones or perhaps even a small speaker.  (added 10/05)

Crystal Set that Requires No Antenna:  (added 2/05)

CW Zero Beat Indicator:  (Electronic Circuit / Schematic added 10/04)

Designing a Superheterodyne Receiver using an IF Sampling Diversity Chipset:  AN-502 - Analog Devices Application Notes  (Circuit / schematic design added 6/06)  The AD6600/AD6620 Chipset Simplifies Receiver Design

Four Band Double Tuned Preselector:  (Electronic Schematic / circuit added 4/02)

Four Channel Wireless Transmitter and Receiver:  (Circuit / schematic design added 6/06)

HDT Technology Adds Power to CDMA Chip Set:  RF Micro Devices Application Note TA0003 (Electronic circuit design added 02/05)

How to Build a 300MHz AM RF Remote Control System:  (Electronic circuit added 4/05)

I.F. Amplifier:  The I.F. transformer primary has 18 turns, the secondary winding has 4 turns. The capacitors across the IFT primaries are 82pF. The input/output transformer has 12 turns, tapped at 3 turns from ground. This transformer is wound on a ferrite core. The MOSFETs are 3SK45's. The diodes in the product detector are 1N34's. I use a six pole SSB filter from a scrap CB. The centre frequency is 7.8MHz. The -6db bandwidth is about 2.5KHz. (Electronic circuit design added 02/05)

I.F. Amplifier:  The I.F. transformer primary has 18 turns, the secondary winding has 4 turns. The capacitors across the IFT primaries are 82pF. The input/output transformer has 12 turns, tapped at 3 turns from ground. This transformer is wound on a ferrite core. The MOSFETs are 3SK45's. The diodes in the product detector are 1N34's. I use a six pole SSB filter from a scrap CB. The centre frequency is 7.8MHz. The -6db bandwidth is about 2.5KHz. (added 2/05)

IF Amplifier Circuit:  Three of these amplifiers are used in series to build the 455 kHz IF amplifier. AGC voltage comes from the AGC Circuit. The diagram above shows the circuit for the second IF amplifier. (Electronic circuit design added 02/05)

Lightening Detector:   A VLF receiver tuned to 300 kHz designed to detect the crackle of approaching lightning. A bright lamp flashes in synchrony with the lightning bolts indicating the proximity and intensity of the storm. It has a superior RF section with a single resonance near 300kHz and plenty of sensitivity. The antenna is a telescopic antenna that extends to two or three feet. The prototype is built into a phenolic box using point-to-point wiring. The power switch is a single pole, double throw type with a center-off position. The power supply is connected to the center terminal and the speaker is connected to one of the outer terminals. Both of the outer terminals are also connected to the other circuitry through a couple of silicon diodes, one from each terminal. One diode keeps the speaker from getting power in the 'speaker off' position and the other diode is simply there so that the circuitry sees the same voltage in both 'on' positions.  Alternately, a switch could be added in series with the speaker to turn it off. After one storm, you will add the switch if you don't include it at first! (added 6/03)

Linear Circuit Devices for Applications in Battery Powered Wireless Systems:  Microchip Application Note - Published 24-Feb-03   (added 2/06)

LM1823High Quality TV Video I.F. Amplifier and Synchronous Detector for Cable Receivers:  National Semiconductor Application Note 09 Apr1996 / (Circuit / schematic design added 6/06)

Low Distortion IF Amplifier/ADC Driver with Digitally Controlled Gain:  Linear Technology LT5524 (Electronic circuit design added 02/05)

MRX 40 Mini Receiver:  (added 8/03)

One Transistor FM Receiver:  (Electronic Schematic / circuit added 4/02)

One Transistor Regenerative Receiver:  (added 8/03)

OpAmp Radio:  (Electronic Schematic / circuit added 4/02)

Phase Shift Radio Direction Finder:  (Electronic Schematic / circuit added 4/02)

Q  Multiplying Loop Antenna:  (Electronic Schematic / circuit added 4/02)