GX434 Datasheet, PDF (6/9 Pages) Gennum Corporation – GX434 Monolithic 4x1 Video Multiplexer

10 mV/div
0.1 V/div
0.5 µs/div
Fig.3 Switching Transient (crosspoint to crosspoint)
Chip disabled crosstalk = 20 log
V_IN
V_OUT
V_OUT
ENABLED
V_IN
CROSSPOINT
37.5 Ω
Fig. 5 Chip Disabled Crosstalk Test Circuit
1 µs/div
Fig. 4 Switching Envelope (crosspoint to crosspoint)
All hostile crosstalk = 20 log
R_IN
V_OUT
V_IN
V_OUT
V_IN
R
L
≥10
kΩ
Fig. 6 All Hostile Crosstalk Test Circuit
BLANKING LEVEL
10 µH
10 µH
LUMINANCE LEVEL
8V
CONTROL BIT
FROM I/O PORT
R.F. SIGNAL
SOURCE
75 Ω
3.9 kΩ
220 Ω
RELAY SWITCH
150 Ω
0.1µF
AC
COUPLING
150 Ω
DUT
R
L
C_L
BUFFER
AMP
x2
75 Ω
75 Ω
Fig. 7 Differential Phase and Gain Test Circuit
DIFFERENTIAL GAIN AND PHASE TEST CIRCUIT
The test circuit of Figure 7 allows two DC bias levels, set by
the user, to be superimposed on a high frequency signal
source. A computer controlled relay selects either the preset
blanking or luminance level. One measurement is taken at
each level and the change in gain or phase is calculated.
This procedure is repeated one hundred times to provide a
reasonably large sample.
The results are averaged to reduce the standard deviation
and therefore improve the accuracy of the measurement.
The output from the device under test is AC coupled to a
buffer amplifier which allows the buffer to operate at a
constant luminance level so that it does not contribute any dg
or dp to the measurement.
510 -34 -2
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