HP TM 11-6625-2779-14&P - Manual (Page 9)

Model 3555B Section I
SECTION I
GENERAL INFORMATION
1-1. INTRODUCTION.
1-2. The Hewlett-Packard Model 3555 B
Transmission and Noise Measuring Set is a versatile set
designed for uses in testing telecommunications
equipment. The extreme sensitivity of this set, linked
with its wide and flat frequency response, make it
suitable for noise and level measurements at voice,
program and carrier frequencies. Levels from -80dBm
to +30dBm (10dBm to +120dBm) full-scale can be
measured and displayed on a meter calibrated to
indicate both in dBm for level measurements and in
dBm for noise measurements.
1-3. The set combines the features of a voice and
noise frequency measuring set and the features of a
carrier frequency measuring set. For voice and program
frequencies impedances of 900 ohms and 600 ohms are
provided, balanced or unbalanced, bridged or
terminated. For noise measurements a noise-to-ground
(Ng) function is provided which provides 40dB of
attenuation for longitudinal noise. For carrier
frequencies 600 ohm, 135 ohm and 75 ohm impedances
are provided. The 600 and 135 function can be either
balanced or unbalanced, bridged or terminated; The 75
function is unbalanced only. Bridging impedance is over
100 kilohms, allowing measurements with a bridging
loss of less than 0.05dB. The meter indicates in dBm
for any selected input impedance.
1-4. The 3555B includes a 3kHz flat, a C-Message, a
Program and a 15kHz flat filter, each easily selectable
by a front panel control. These filters conform to the
standards set up .by the Bell System and Edison Electric
Institute. Other filters are available upon request.
Figure 1-1. Model 3555B Transmission and Noise Measuring Set
1-1