> On 7/5/06, Wouter van Ooijen <wouter@voti.nl> wrote:
>> > The input signal is 20v peak-to-peak (-10v to +10v)  ac 14Mhz
>> > rf signal.
>> > and i want to shift it to ( -15v to +5v ).  I looking for a
>> > way to do it
>> > without using additional power supply.
>>
>> a suitable transformer, with the 0 of the secondaryt at -5V?
>
> +10v - (-10V) = 20V swing
> +5V - (-15V) = 20V swing too
>
> Pass the signal via a capacitor and fixe the DC level at the right
> value(ie  -5V).
> The question is how you've get 20Vpp/14Mhz RF signal (meaning sinusoidal)
> and what you're doing with it.
>
> Vasile
> --

Could also use a clamper circuit. Run the AC through a coupling capacitor,
then a diode to +5V. This limits positive swing to +5V and maintains the
peak to peak volage swing. Kinda like "grid leak bias." Should also have a
large resistor to ground after the capacitor.

Harold


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