Tektronix TDS 500C User Manual

Page of 352
Acquiring and Displaying Waveforms
TDS 500C, TDS 600B, & TDS 700C User Manual
3–29
A TDS 500C or TDS 700C Oscilloscope can interleave its channels to attain
higher digitizing rates without equivalent time sampling or interpolating. The
oscilloscope applies the digitizing resources of unused channels (that is, channels
that are turned off) to sample those that are in use (turned on). Table 3–2 lists
how interleaving more than one digitizer to sample a channel extends the
maximum digitizing rate.
Once you set horizontal scale to exceed the maximum digitizing rate for the
number of channels in use (see Table 3–2), the oscilloscope will not be able to
get enough samples to create a waveform record. At that point, the oscilloscope
will either interpolate to calculate additional samples or it will switch from real
to equivalent time sampling to obtain additional samples. (See Interpolation on
page 3–28 and Equivalent-Time Sampling on page 3–27.)
Table 3–2:  How interleaving affects sample rate 
No. of 
a
el
Maximum digitizing rate
1
channels on
TDS 520C &
TDS 724C
TDS 540C
TDS 754C
TDS 784C
One
1 GS/sec
2 GS/sec
2 GS/sec
4 GS/sec
Two
500 MS/sec
1 GS/sec
2 GS/sec
2 GS/sec
Three or Four
Not Available
500 MS/sec
1 GS/sec
1 GS/sec
1
When real-time sampling. (GS = Gigasamples; MS = Megasamples.)
All oscilloscopes in this manual support the following four acquisition modes:
Sample, Envelope, Average, and Peak Detect. TDS 500 C and TDS 700C
Oscilloscopes also support Hi Res. Keep in mind which modes apply to your
model oscilloscope as you read the following descriptions.
Sample (the mode most commonly used), Peak Detect, and Hi Res modes
operate in real time on a single trigger event, provided that the oscilloscope can
acquire enough samples for each trigger event. Envelope and Average modes
operate on multiple acquisitions; the oscilloscope averages or envelopes several
waveforms on a point-by-point basis. (For TDS 500C and TDS 700C models
only, Hi Res, Envelope, and Average modes are not available when in InstaVu
mode; see Incompatible Modes on page 3–58.)
Interleaving
The Acquisition Modes