Maker Pro
Maker Pro

DIGITALY CONTROLLED RADIO RECEIVER

R

RealInfo

Jan 1, 1970
0
Hi all

My question is about the structure of a digitally controlled radio like this
http://www.hamradio.com/detail.cfm?pid=H0-010818

From the point of view of the micro controller that controls it .

If I understand well that micro does 3 main things
1> controls the frequency of the PLL that functions as a local oscillator
used by the rf mixer
2> sends the relevant data to the LCD .

3> respnds ti the buttons .

I want to concentrate on the first two .

How the micro controls the PLL so it will produce the exact frequency
that the LCD displays.

And how the micro translates the frequency knob to a chosen frequency .

Thanks
Elico
 
J

Jasen Betts

Jan 1, 1970
0
Hi all

My question is about the structure of a digitally controlled radio like this
http://www.hamradio.com/detail.cfm?pid=H0-010818

From the point of view of the micro controller that controls it .

If I understand well that micro does 3 main things
1> controls the frequency of the PLL that functions as a local oscillator
used by the rf mixer
2> sends the relevant data to the LCD .

3> respnds ti the buttons .

I want to concentrate on the first two .

How the micro controls the PLL so it will produce the exact frequency
that the LCD displays.

typically the PLL is a VCO which is divided and compared with a fixed
clock, the microcontroller will program clock divider - it may even
use an internal counter to do this. this divided clock is compared
with a reference clock and the difference is fed back to control the VCO
And how the micro translates the frequency knob to a chosen frequency .

probably some sort of quadrature encoder and a the micro just counts
up or down as the knob is turned.
 
T

Tauno Voipio

Jan 1, 1970
0
Hi all

My question is about the structure of a digitally controlled radio like this
http://www.hamradio.com/detail.cfm?pid=H0-010818

From the point of view of the micro controller that controls it .

If I understand well that micro does 3 main things
1> controls the frequency of the PLL that functions as a local oscillator
used by the rf mixer
2> sends the relevant data to the LCD .

3> respnds ti the buttons .

I want to concentrate on the first two .

How the micro controls the PLL so it will produce the exact frequency
that the LCD displays.

And how the micro translates the frequency knob to a chosen frequency .

Thanks
Elico


Many of the current designs are using Direct Digital Synthesis (DDS)
instead of a PLL, though also PLL designs are used. The details of
frequency set-up depend on the frequency generator chip (or chipset)
chosen and the selected frequency generation scheme.

For a primer on DDS, see:
<http://www.analog.com/library/analogDialogue/archives/38-08/dds.html>

There are also links to chip datasheets and app notes for controlling
them.
 
R

RealInfo

Jan 1, 1970
0
Hi all



My question is about the structure of a digitally controlled radio like this

http://www.hamradio.com/detail.cfm?pid=H0-010818



From the point of view of the micro controller that controls it .



If I understand well that micro does 3 main things

1> controls the frequency of the PLL that functions as a local oscillator

used by the rf mixer

2> sends the relevant data to the LCD .



3> respnds ti the buttons .



I want to concentrate on the first two .



How the micro controls the PLL so it will produce the exact frequency

that the LCD displays.



And how the micro translates the frequency knob to a chosen frequency .



Thanks

Elico

Many thanks you all
Elico
 
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