HT instruments HT157 - Manual (Page 6)

HT155 - HT157
EN - 4
2. GENERAL DESCRIPTION
This manual refers to models HT155 and HT157. In the manual, the generic term
“instrument” refers to both devices and, if not otherwise indicated, characteristics are to be
considered as common to both models
The instrument has the following functions:
 Measurement of sound pressure level (SPL) Type 1
 Real-time and statistic analysis
 Octave band and in 1/3 octave band analysis (HT157 only)
 Measures weighted in frequency by means of A, C and Z curves and F, S impulses
 Fast, Slow, Impulse, PeakC+, Peak C- integrations
 Measurement of noise equivalent levels (Leq)
 Inner memory for saving measures and recordings
 AC analogue output for connection to external dataloggers
 USB interface for connection to PC and/or USB pen drive
 Wide backlit LCD display
The front panel of the instrument bears the function keys for the selection of the above-
listed functions (see chapter 4.2). The measured value appears on the wide LCD display
with the indication of the measuring unit and of the enabled functions.
In the lower part of the instrument there are the terminals for the AC analogue output with
3,5 mm coaxial connector and the (USB) ports for the connection of a possible DC 5V
external adapter for power supply without using the internal battery and RS-232 (non-
active output)
In the rear part of the instrument there is a hole for installing the instrument onto a possible
tripod while measuring.