[radioastro] Radio Jove Kit receiver theory of operation
- From: Victor Herrero <hubbleed@xxxxxxxxx>
- To: Akhil Chopra <akhilchopra19@xxxxxxxxxxx>, Radio Jove Technical <Radio_JOVE@xxxxxxxxxxxxxxx>
- Date: Tue, 24 Nov 2009 09:00:32 -0700
Hi Akhil, and all Radio Jove participants,
I refer to the Receiver Manual written by Richard Flagg, who designed the
receiver:
http://radiojove.gsfc.nasa.gov/telescope/rcvr_manual.pdf July 2006
You should study carefully the Theory of Operation on pages 3 to 5.
Notice in the block diagram (Figure 1) that the radio frequency preamplifier
(integrated circuit J310) feeds the local oscillator and mixer integrated
circuit NE 602.
The output of NE 602 is an audio frequency. Because the conversion from
radio frequency to audio frequency is done in a single step, the receiver is
called a direct conversion receiver.
Other receivers use one or more intermediate frequency amplification and
filtering stages. They are more expensive, this is an low cost receiver.
Re: "so we produce a carrier of same frequency which we want and mix it with
the incoming signal carrier"
I would say: The NE 602 produces a local oscillator sine wave (of the
desired frequency) that is mixed with the output signal from the J310
preamplifier to produce an audio signal output.
Re: "if you can provide me some reference book or material which was used
while developing it"
Richard developed this receiver using his several decades of experience in
developing electronic circuits.
The American Radio Relay League (ARRL):
http://www.arrl.org/
is one organization that publishes many excellent texts and manuals that you
could study. See their catalog:
http://www.arrl.org/catalog/index.php3?category=Technical%2C+Electronics%2C+and+Communications+Reference
There are description of the NE 602 integrated circuit at:
http://www.electronics-tutorials.com/devices/602.htm
http://www.pan-tex.net/usr/r/receivers/ra01091.htm
There is an 11 page data sheet for the 602 at:
http://www.nxp.com/documents/data_sheet/SA602A.pdf
Many thanks for your questions.
Keep asking, let us learn together.
Victor
Victor Herrero
//www.freelists.org/archive/radioastro
http://herrero.freei.me/
On Mon, Nov 23, 2009 at 12:13 PM, Akhil Chopra <akhilchopra19@xxxxxxxxxxx>wrote:
>
> thank you sir.
>
> i will definatly read that book recomended by you in your last e-mail to
> me..
>
> sir i have my very first problem in building this reciever is understanding
> the name given to it as direct conversion reciever, i studied alot about it
> i understood alot but still i feel like something is missing in my
> knowledge.. if you can explain me somthing about direct conversion reciever
> in context with radio jove reciever and which part of it is acting as a
> circuit for making it DCR?
>
> i know the ic sa602 acting as a local oscillator and mixer so we produce a
> carrier of same frequency which we want and mix it with the incoming signal
> carrier but how is it actually done in the circuit?!
>
> if you can provide me some reference book or material which was used while
> devloping it then it would be a great help for me..
>
> i want to learn it and understand it thoroughly..
>
>
>
>
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