I am happy to be able to make my own transistor
design.
It is no problem to be better than
" National "
.
The trouble is I am not able to explain
my circuit in english
. So only experts can see
what happens here.
Have a look at Q69 and Q670 for example:
They replace several IC's
an analog switch IC, a few opamps, a Schmitt trigger
and a white clip stage ...
The stage Q66 Q67
David only uses one transistor to replace the diode.
Davids stage is 500 times better than a diode!
(500 is the B of BC547C)
and the stage I used is 250000 times better than a
diode. Do you understand this?
The audio modulator Q64 combines a modulator
and a so called " infinitive detector "
I have made a DC-coupled negative feedback from the
detector to the input. The audio stages are Loftin-
White stages.
This is high end hifi design
In the IC applicationes you would need a additional
receiver to make this...
The modulator transistors are similar to the
g1 modulation used in (vintage) transmitters.
What I wounder about is that nobody has seen
the inputs.
At the video input you must have 75Ohm
The video output must have 75 Ohms too.
If you load the output with 75 Ohms you get
1Vpp video at peak white. This is a standard!!!!!!!
The audio input impedance must be more than
50KOhms for scart and RCA plugs.
If there is a 1KOhm poti and a low input resistance
you get loss in bass and the outout stage is overloaded.
Note that a typical audio
output has a 2uF cap!
Sorry for my bad english...
Look here, I drawed a block diagram for the
modulator video section.
The input filter and Blatt 8 will be added soon
in the Normwandler website.
www.pixum.de/viewalbum/?id=1137100
Kind regards
Darius