and from +40dBV/dBm to -130dBV/dBm in the Log
mode.

Figure 3-11. Noise vs. Frequency.

3-46. Dynamic Range. 3-47. For operating purposes, the dynamic range of a wave  analyzer can be defined as the ratio of the largest to  smallest signals it can measure for a given range setting. The largest signal that can be measured (full-scale sensitivity) is determined by the INPUT SENSITIVITY, amplitude VERNIER and AMPLITUDE REF LEVEL settings. The smallest signal that can be measured is determined by: a. instrument-induced distortion and spurious
b. display range
c. internal noise floor (maximum sensitivity)

3-48. Distortion and Spurious. When the OVERLOAD light is off, the instrument-induced distortion and spurious is more than 80 dB below full scale.
3-49. Display Range and Noise Floor. When the volts scale is selected, the smallest signal that can be measured is approximately 10% of full scale. Thus, the dynamic range is about 20 dB as long as the noise floor is more than 20 dB below full scale. When the Log 90 dB scale is selected, displayed readings of less than -80 dB are not specified. The dynamic range is 80 dB as long as the noise floor is more than 80 dB below full scale. When the Log 10 dB scale is selected, the dynamic range is 10 dB as limited by the display range.

3-50. Meter Scales.

3-51. Refer to Figure 3-12 for the following discussion.  The 3581 SCALE buttons permit selection of three scale  settings:
Volts (linear).
Log 90 dB and
Log 10 dB.

3-52. Voltage Scales. When the Volts SCALE button is  pressed and the amplitude VERNIER is in the CAL