Tektronix 494AP service manual O a o e, O o o a

Specification - 494A1494Ap
Service, Vol. 1
	Table 2-3 (Continued)
	INPUT SIGNAL CHARACTERISTICS
Characteristic	SupplementalInformatlon
HORIZITBIG(RearPanel)
	Dc coupled input for external hor-
	izontal drive (selectedby the EXT
	positionof the front-panelTIME/DIV
	control) and ac coupled input for
	externaltrigger	signals(selected
			at
	otherpositionsof the TIME/Dlvcon-
	trol).
SweepInputVoltageRange	0 to +10V (dc * peak ac) tor tutl
TriggerInputVoltageRange	screendeflection
Minimum	At least 1.0 V peak from 15 Hz to
	1 MHz
Maximum
dc + peakac	5 0 v
	30 vrms to 10 kHz, then derate
	linearlyto 3.5 Vr." at 100 kHz and
	above.
PulseWidth	0.1rs minimum
MARKERIVIDEO(RearPanet)
	External Video input or		External
	VideoMarkerinpul,switchedby pin
	1 0f the J104ACCESSORYconnec-
Video lnput Level	tor.
	0 t o * 4 V
MarkerInputLevel	0 t o - 1 0 V

t

o o

I

a

a

t

o a

I

I

I

o

I

o o ,o

o o o a o e

J104 ACCESSORY(Rear Panet)

Pin1

Pin 2

Pin3

2-12

lnterfaces with Tektronix 1405 Side- band Adapter.

25-pin connector

(Not R5-232 compatible)

Provides bi-directionalaccess to the instrumentbus. Also provides exter- nal Video select and external preselector drive. Except for the external preselectordrive output, all lines are TTL compatible.

Maximum voltage on all lines is

+' l 5v . ExternalVideo Select

Low selectsExternalVideo lnput. High (default) selects Video Marker Input.

ExternalPreselectorDrive

Drivesignalfor an externalpreselec- tor. Outputvoltageis proportionalto frequencychange (only in Bands

2-s\.

ExternalPreselectorReturn

Ground return for the External Preselectorsiqnal.

o o

I

t

o a o

a

o o o o o a

C

o o o

a

t

o