Instruction manual

Introduction and Specifications
1-4
1720/1721
Table 1- 1: Signal input
Characteri sti cs Performance requirement Supplemental information
Step
number
Return loss (75Ω)
Video inputs (CH A, CH B)
EXT REF
Atleast40dBfrom50kHzto6MHz. Loop-through terminated in 75W. Input
in use or not in use, instrument power
on or off, all deflection factor settings.
11
Crosstalk between channels Greater than 70 dB of isolation be-
tween channels. M easured at F
SC
between Channel A, Channel B, and
EXT REF.
Loop-through isolation Greater than 70 dB of isolation be-
tween loop-throughs. Measured at F
SC
between Channel A, Channel B, and
EXT REF.
Input requirements Stable displ ay wit h composi te video, or
black burst with 286 mV (300 mV PAL)
burst ±6dB.
3
DC input impedance (unterminated) Greater than 15 kΩ
EXT REF input Composite video (can be CW subcarr-
ier if two internal jumpers are moved).
Absolute maximum input voltage ±12 VDC plus peak AC
Maximum operat ing i nput vol tage Peak AC + DC should be within
+8.0 V and -- 5.6 V for proper operation.
Table 1- 2: Vector mode
Characteri sti c Perform ance requirement Supplemental information
Step
number
Chrominance processing characteris-
tics
Nominal subcarrier frequency (F
sc
)
NTSC
PAL
3.579545 MHz.
4.43361875 MHz.
Chrominance bandwidth
Upper --3 dB point
Lower --3 dB point
F
sc
+500 kHz, ±100 kHz
F
sc
--500 kHz, ±100 kHz
4
Display
Vector phase accuracy
Vector gai n accuracy
Quadrature phasing
±1.25 Measured with color bar signal
Typically, ±2.5%
Typically, ±0.5°
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