A
Alessandro Esposito
- Jan 1, 1970
- 0
HI need to shift the phase of a signal between 0 to 180°. I usually work
with sinuswave between 10KHk and 100MHz.
I found out it is possbile to build a so called allpass filter to make this:
R1
+----\/\/\-+
| -\ |
R1 | | \ |
+-\/\/\+-|- \ |
Vin ---+ | >--+--- Vout
+-\/\/\+-|+ /
C | | /
| -/
\
/ R2
\
|
GROUND
in which R2 is variable and control the phase delay.
I have to question:
1) I do not have formulas to setup the values of C and Ri... is, for
example, R1 the input impedence of the circuit?
2) Is it possible to use this circuit up to 100MHz? Which opamp could work?
A less important aspect:
I would like to modify this phase via a PC: Do you think is is reliable the
use of a DAC to control the voltage on a FET base to use it instead (or
with) R2?
Thanks
Alessandro
with sinuswave between 10KHk and 100MHz.
I found out it is possbile to build a so called allpass filter to make this:
R1
+----\/\/\-+
| -\ |
R1 | | \ |
+-\/\/\+-|- \ |
Vin ---+ | >--+--- Vout
+-\/\/\+-|+ /
C | | /
| -/
\
/ R2
\
|
GROUND
in which R2 is variable and control the phase delay.
I have to question:
1) I do not have formulas to setup the values of C and Ri... is, for
example, R1 the input impedence of the circuit?
2) Is it possible to use this circuit up to 100MHz? Which opamp could work?
A less important aspect:
I would like to modify this phase via a PC: Do you think is is reliable the
use of a DAC to control the voltage on a FET base to use it instead (or
with) R2?
Thanks
Alessandro
