5 PICOSCALE HARDWARE
Table 5.2: Main performance data DDI
Parameter
Typical Value
Unit
Comment
V
O
Diff
0 - 5
V
Differential output voltage
V
IH
Diff
0.2
V
Differential high-level input voltage
V
IL
Diff
-0.2
V
Differential low-level input voltage
f
max
5
MHz
Max. frequency per differential pair
BOB AquadB
Industry standard AquadB receivers are often able to receive differential quadrature signals as
provided by the
PICO
SCALE
Controller. In figure 5.6 the AquadB signals are shown schematically.
With the signals A and B four states can be
encoded, each state indicates a position increment. So
the maximal increment frequency is 4 times the maximum di
ff
erential pair frequency, in this case
20 MHz.
Figure 5.6: Scheme of the di
ff
erential A and B signal and the according position increment of the
Quadrature interface.
The direction of the position change is given by the order of the cases.
BOB Serial Data
Figure 5.7: Clock and data cyles on the serial interface. The CLOCK L
I
NE can either have a negative
zero level or a positive zero level. The DATA L
I
NE can either be written with rising or the
falling edge of the clock.
Each of the three DSub 15 connectors can be con
fi
gured to act as a serial data output.
I
n
fi
gure
5.7 the options are illustrated. The upper part of the
fi
gure shows the options of the clock line and
37
PicoScale User Manual
