Re: Front End (TUNER)

"Myauk" <aungkokothet@xxxxxxxxx> wrote in news:1174627870.460950.97910
@e65g2000hsc.googlegroups.com:

Thank you so much for the information.
Now I managed to find an application note for a DVB-T Tuner from
infineon.
I intended to expand my scope of knowledge. (not in depth in RF)
What I am interested there is how to configure the settings for
respective blocks in the tuner.

Reverse encgineer the tuner. Of find a data*** on it.

I am quite eager to know how the I2C serial bit stream is recognized
by different control blocks in the front module.

It isn't. I2C only controls the PLL IC, which may have GPIO to control
band selects.

And I wish to know the scheme that the processing unit sends commands
to the front end module, and how it understands the commands from the
programming point of view.
With RF receiving system, I understand the basic block diagram but
wish to know more about it.

In a nutshell, it is a couple voltage tuned filters, feeding a mixer
supplied by a voltage tuned oscillator. The PLL IC, via I2C, tunes the
voltage tuned oscillator, and by proxy, the tuned filters. The output of
the mixer goes into an IF strip, and a video detector. There may be a
number of bands using different coils in the tuned filters, selected by
PIN diodes, which are controlled by GPIOs on the PLL chip, or discrete
inputs on the module.

I am not going to design a front end module but I am interested in the
power supply (usually 5 to 33V boost converter) of it.
I would like to have the relationship between the power supply
specifications and the tuner performance.
However, now I have one applications notes which encourages me to find
more information on it.
Thans for your initiation.
Regards

As said, the 33V is just to tune the varicaps. It requires a higher
voltage to tune higher frequencies. It only needs to be a few ma for
that. The 5V can be a standard 5V supply, although if your project has
sigificant digital, it should be a separate analog 5V.

.

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