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Theory of Operation
2715 Spectrum Analyzer Service Manual
3-53
At the end of a horizontal bin the contents of the Max Accumulator will be
written to waveform memory.
If the acquisition mode is Min Peak the same comparisons occur as in Max Peak
acquisition mode, except that the Min Accumulator is used. At the end of a
horizontal bin the contents of the Min Accumulator will be written to waveform
memory.
If the acquisition mode is Min/Max then the same comparison occur as in Max
Peak acquisition mode, except that both the Min and Max Accumulators are
used. At the end of a horizontal bin the contents of either the Max or Min
Accumulators will be written into waveform memory, depending on whether the
horizontal bin was even or odd and whether noise was detected or not. Noise is
defined as both the Min and Max Accumulator being written with a new value
sometime during the horizontal bin. Table 3--13 shows the algorithm used to
write data to the waveform memory at the end of a horizontal bin.
Table 3- 13: Input Conditions Required to Write Either the Max or Min
Accumulators to Waveform Memory
Horizontal Bin Signal Type Waveform Written From
Odd Noise Max Accumulator
Odd Signal Max Accumulator
Even Noise Max Accumulator
Even Signal Max Accumulator
If the acquisition mode is Sample the incoming data is automatically placed in
the Max Accumulator, regardless of its value. At the end of the horizontal bin,
the contents of the Max Accumulator are written to waveform memory. This
effectively places the last acquisition, from the ADC, into waveform memory.
The timing diagram in Figure 3--19 shows the sequence of events required when
writing data to the waveform memory.