Tektronix 744A User Manual

TDS 684A, TDS 744A, & TDS 784A Service Manual

This subsection contains tables that list the various typical characteristics which
describe the TDS 684A and 7XXA Digitizing Oscilloscopes.

Typical characteristics are described in terms of typical or average performance.
Typical characteristics are not warranted.

The limits are given in the following table for signals having amplitude greater than
5 divisions, reference level = 50%, filter set to (sinX/X), acquired at 5 mV/div or greater.
For the TDS 7XXA, pulse duration < 10 div. Channel skew not included.

For the Single Shot condition, 1.4 

≤

 T

r

/S

i

 

≤

 4, where S

i

 is the sample interval and T

r

 is

the displayed rise time.

TDS 684A: For the averaged condition, 1.4 

≤

 T

r

/W

i

 

≤

 40, where W

i

 is the Waveform

Interval, as described elsewhere in these specifications.

TDS 684A: Extra error in the measurement will occur for two-channel measurements due
to channel-to-channel skew. This is described elsewhere in these specifications.

Single Shot or Sample
mode (or HiRes mode
on the TDS 7XXA),
Full Bandwidth se-
lected

TDS 684A:

±

( (0.20 

×

sample interval) + (100 ppm 

×

 | Reading |)

+ (0.05 

×

W

i

 ) )

TDS 684A example: at 5 GS/s, 5 ns/div, measuring a 40 ns wide
pulse, accuracy = 

±

( 40 ps + 4 ps + 5 ps) =  

±

49 ps.

TDS 7XXA: 

±≥

0.15 sample interval + 25 ppm 

×

 | Reading | +

t/div/1000

TDS 7XXA example: at 4 Gs/s, accuracy = 37.5 ps

≥

100 Averages, Full

Bandwidth selected.
TDS 7XXA: repetitive

TDS 684A: 

±

( 10 ps + (100 ppm 

×

| Reading |)  + (0.25 

×

W

i

 ) )

TDS 7XXA: 20 ps + (25 ppm 

×

 | Reading |) + t/div/1000

Calculated Rise Time

10 mV/div – 1 V/div

5 mV/div – 9.95 mV/
div

2 mV/div – 4.98 mV/
div

1 mV/div – 1.99 mV/
div

450 ps

600 ps

750 ps

900 ps

800 ps

800 ps

800 ps

890 ns

400 ps

530 ps

600 ns

800 ns