Doepfer A-196 PLL - Manual (Page 5)

doepfer System A - 100 PLL A-196
5
4. Controls
1 Range • 2 Offs.
The frequency range of the internal VCO is selected
with the switch 1.
Control 2 is used to adjust the frequency offset, i.e.
the maximum frequency within the range selected
with the switch 1. The table shows the VCO frequen-
cies obtainable with different settings of range and
offset (with a control voltage ~ 0...+5V at input !).
3 Type
The type of Phase Comparator (PC) is selected with
this switch. Three PC types are available:
• PC 1 Exclusive or gate (Exor)
• PC 2 RS Flipflop
• PC 3 more complex digital network
Each phase comparator has its special advantages
and disadvantages. E.g. PC1 locks even at harmonics,
i.e. integer frequency multiples of the external signal
and the internal VCO. This is a disadvantage for the
standard PLL idea but may be useful for certain musi-
cal effects. One has to find the most suitable PC for
each application.
4 LED
This LED lights up if the PLL is locked for PC2, i.e. if
the frequency of the external signal is identical to the
frequency of the internal VCO.
5 Frequ.
This control is used to adjust the frequency of the
internal low pass filter.
The internal LP can be replaced by an external LP. The
external LP has to be DC coupled and work even at
very low frequencies (some Hz range)! Consequenctly
normal audio VCFs are not suitable. The VC slew
limiter A-171 can be used instead. The "raw" PC output
&
or the pre-filtered output % can be used as input for
the external filter/slew limiter. In this case the output of
the external filter/slew limiter is used as control input !
for the VCO.
Range Offset = 0 Offset = 5 Offset = 10
low 2 Hz - 50 Hz 2 Hz - 200 Hz 2 Hz - 1 kHz
mid 20 Hz - 500 Hz 20 Hz - 2 kHz 20 Hz - 10 kHz
high 200 Hz - 5 kHz 200 Hz - 20 kHz 100 Hz - 100 KHz