Receptor FM cu TDA7000

Aceasta pagina a fost preluata de pe site-ul lui Harry Lythall, http://www.sm0vpo.com

My VHF FM Wireless Microphone project became about the most popular of my transmitters, probably because it is so simple. Here is a very simple VHF FM receiver which is little more than a single IC and a "slack handfull" of capacitors. Note that an external amplifier is a really necessity since the unit only delivers about 70mV of AF.

The 10K resistor (*) is only required if you want the receiver to mute (squelch) under no-signal conditions. You could add a 100K in series with this resistor to get an adjustable squelch. This circuit will JUST drive a crystal earphone or high impedance headphones directly, but an output isolating capacitor (100nF) is needed for any other device. L1 is 6 turns No 18 SWG enamelled wire on a 5mm former, but you may have to play with the values a bit. I used a coil fabricated on the PCB itself, tuned with a trimmer capacitor.

All the other components are just a bunch of capacitors which are fitted to the board at the other side of the chip, just to make it look a bit prettier.

SpecificationMinTypMax
Supply Voltage 2.0v 4.5v 10v
Supply Current - 8mA -
Frequency Range 1.5MHz 88-108MHz 120MHz
Sensitivity (3dB S/N) - 1.5uV -
Sensitivity (26dB S/N) - 5.5uV -
Mute Sensitivity - 6.0uV -
AFC Range (110MHz) - +/-300KHz -
Selectivity 45dB - -
AM Suppression 50dB - -
Max I/P Signal 200mV - -
AF Output - 75mV -

As you can see, this receiver is VERY sensitive, small and seems to work very well indeed. It is in fact a full superhet receiver with a very low RC tuned IF. The Image signal is rejected by the action of the AFC which functions to push it away. With suitable antennas and terrain, with this receiver you could easily get the full 500 meters from the FM wireless microphone v5. I am offering this receiver in kit form, including solder, antenna wire etc. All you will need to provide is the battery, tools and soldering iron. Here is the kit version fully assembled.

Download

datashet TDA7000

comentarii

  • Costi

    Am construit si folosit acest programator pentru mai multe pic-uri in combinatie cu WinPic800, fara probleme. Acum am desktop-ul defect si incerc sa-l folosesc de pe laptop cu un adaptor usb-serial cu cipul PL2303 de la Prolific. Am toate 9 semnalele pe mufa seriala. Vad portul serial ca functioneaza, softul de programare deschide portul dar nu pot citi sau scrie microcontrolerul. Trebuie sa fac ceva setari deosebite? Cat trebuie sa fie baudrate la portul serial? Am incercat si cu IC-Prog si PonyProg si tot nu merge.

    2013-09-16 17:08:08

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