Chapter 5 311
Programming
Data Transfer to Computer
Example 7 converts binary values to measurement data and prints
them on the computer display.
EXAMPLE 7
10 INTEGER Trace_a(1:601)
20 DIM Real_num(1:601)
30 Ref_lvl=0 !0 dBm reference level
40 Log_scale=10 !10dB/division log scale
50 OUTPUT 718;"TDF B;TRA?;"
60 ENTER 718 USING "#,W";Trace_a(*)
70 MAT Real_num= Trace_a
80 FOR X=1 TO 601
90 Real_num(X)=Ref_level+Log_scale*(Real_num(X)/60-10)
100 NEXT X
110 END
For converting linear data, use this equation:
where:
x = binary data in an array element.
RL = reference level. When RL is in volts, n will be in volts.
These equations are useful when you are interested in viewing only a
few points of data, rather than an entire trace. B-format saves time and
memory, and these equations provide a means to view the data, if
necessary.
NOTE It is not possible to return data to the analyzer using binary format.
You must use either A-block or I-block format. These two formats are
described below.
See Table 5-2 on page 315 for an example of how data is sent to the
computer using the TDF B format.
TDF A (A-block format): Return Absolute Block-Data Fields in
Measurement Units
The A-block format transmits data in measurement units as binary
numbers in an absolute block-data field, or field of a known size, similar
to the binary format. Each data point is sent as two 8-bit bytes; the
most significant byte is sent first, followed by the least significant byte.
The A-block format also transfers a four-byte header before the 601
points of trace data. The bytes are the ASCII characters "#", "A", and a
two-byte length field specifying the number of data bytes in the block
that follows (that is, 1202).
n RL
x
600
---------
×=
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