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DIGITALY CONTROLLED RADIO RECEIVER

Started by RealInfo March 17, 2013
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 






 
  
On 2013-03-17, RealInfo <therightinfo@gmail.com> wrote:
> 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. -- &acirc;&scaron;&sbquo;&acirc;&scaron;&fnof; 100% natural
On 17.3.13 11:26 , RealInfo wrote:
> 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. -- Tauno Voipio
On a sunny day (Sun, 17 Mar 2013 02:26:27 -0700 (PDT)) it happened RealInfo
<therightinfo@gmail.com> wrote in
<cab942d4-8877-43ba-a798-4396f35408fe@googlegroups.com>:

>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.
programmable divider
>And how the micro translates the frequency knob to a chosen frequency .
rotary encoder.
>Thanks >Elico > > > > > > > > >
On Sunday, 17 March 2013 11:26:27 UTC+2, RealInfo  wrote:
> 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
On Sun, 17 Mar 2013 02:26:27 -0700 (PDT), RealInfo
<therightinfo@gmail.com> wrote:

>My question is about the structure of a digitally controlled radio like this >http://www.hamradio.com/detail.cfm?pid=H0-010818
>How the micro controls the PLL so it will produce the exact frequency > that the LCD displays.
Most such radios have one or more PLL (phase lock loops) that add and multiply to produce the transmit and local oscillator frequency. For the TS-590S, you'll find a block diagram in the owners manual: <http://www.kenwoodusa.com/communications/amateur_radio/hf_base_mobile/ts-590s> <http://www.kenwoodusa.com/UserFiles/File/UnitedStates/Communications/AMA/Manuals/TS-590_In-Depth-Manual.pdf> The "in depth" manual includes a theory of operation section that explains how the PLL synthesizer works. In this radio, there are 3 mixers (triple conversion) that eventually produce the 24KHz IF used by the DSP. There is also a single conversion section for specific bands near the IF frequency. See Section 1.x for details. For more detail and schematics, the full service manual is at: <http://mods.dk> <http://www.mods.dk/downloadmanual.php?RefFil=TS-590S_Service_manual.zip&radio=>
>And how the micro translates the frequency knob to a chosen frequency .
The knob runs a shaft encoder that eventually sets multiple divider ratios (depending on frequency band) to produce the three local oscillator frequencies. The relationship is set by a formula that varies with the type of conversion, frequency range, and tx/rx. The divider ratios set the various PLL's to eventually generate the desired output frequency without also producing spurious and extraneous extra frequencies and noise. There's more to HF radio design than just synthesizing the necessary frequencies. In my never humble opinion, the processor and synthesizer are the easiest parts of the puzzle. This might help: <http://www.edn.com/design/analog/4372294/High-performance-HF-transceiver-design-A-ham-s-perspective> -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558