Tektronix 1705A User Manual
Page 48
Operating Instructions
1705A Spectrum Monitor
2- 9
Table 2- 2: dBm to
v
Conversion
Reading in dBm
v (75
Ω)
v (50
Ω)
Reading in dBm
v (75
Ω)
v (50
Ω)
--- 30
8660
7071
--- 105
1.540
1.257
--- 35
4870
3976
--- 110
0.866
0.707
--- 40
2739
2236
--- 115
0.487
0.398
--- 45
1540
1257
--- 120
0.274
0.224
--- 50
866
707
--- 125
0.154
0.126
--- 55
487
398
--- 130
0.087
0.071
--- 60
274
224
--- 135
0.049
0.040
--- 65
154
126
--- 140
0.027
0.022
--- 70
87
71
--- 145
0.015
0.013
--- 75
49
40
--- 150
0.009
0.007
--- 80
27
22
--- 155
0.005
0.004
--- 85
15
13
--- 160
0.003
0.002
--- 90
9
7
--- 165
0.002
0.001
--- 95
5
4
--- 170
0.001
0.001
--- 100
3
2
--- 175
0.000
0.000
The horizontal graticule scales are divided into ten major divisions, which are
further divided into five minor divisions each. The horizontal scale corresponds
to frequency, with the lowest frequency to the left. Note the arrow in Figure 2-4
that signifies that the frequency ascends toward the right. Both the --60 and --80
dB lines are subdivided with minor division marks. Traditionally, many
spectrum analyzer measurements and specifications are between 6 and 60 dB.
The available sweep for the 1705A is 12 divisions long, which means that not all
of the frequencies that it is capable of displaying can be displayed simultaneous-
ly. Figure 2-5 compares the sweep length to the graticule. It shows the usable
areas of the sweep, as well as the minimum and maximum frequencies of the two
bands.
Horizontal Scales