Doepfer A-188-1 BBD Module - Manual (Page 8)

DOEPFER DOEPFER DOEPFER DOEPFER System A-100 BBD Module A-188-1
8
4. Controls and In- / Outputs
4.1. High Speed VCO Section
1 Delay Clock : manual delay control
% CV1: CV1 input HSVCO
6 Polarity: CV1 polarity
& CV2: CV2 input HSVCO
7 Polarity: CV2 polarity
2 CV: attenuator for CV2
This group of elements is responsible for the clock
frequency generated by the high speed VCO (HSVCO).
knob 1 Delay Clock is used to adjust the clock manually.
Two CV inputs (% CV1, & CV2) are available to control the
clock by external control voltages (e.g. LFO, envelope
follower, random, ADSR, keyboard CV, sequencer,
theremin, ribbon controller, foot controller, Midi-to-CV,
shepard generator ...). The sensitivity of CV1 is
approximately +/– 1V/oct according to the position of the
CV1 polarity switch 6. The diagram on the right side shows
the connection between CV1 and clock frequency. The
straight line represents the perfect 1V/oct graph. The slightly
bended curve is the real behaviour of the HSVCO. If an
absolutely "perfect" 1V/oct control is required an external
precision HSVCO or a VCO with PLL has to be used.
Fig 6: relation between CV1 and Clock Frequency
Both CV inputs are equipped with polarity switches (6, 7).
According to the position of these switches the effect of the
corresponding CV is positive (i.e. increasing CV increases
the clock frequency), off, or negative (i.e. increasing CV
decreases the clock frequency).
! Clk Out: clock output HSVCO
This is the clock output of the HSVCO. It is internally
connected to the clock input of the BBD section. The
waveform is rectangle with about
± 3V level. The rectangle
slopes flatten with increasing frequency and the waveform
turns more and more into triangle. Even the load on the
output has influence to the waveform and level.