The communication helmet is essentially a headgear that covers all the head surface, except for a face, and has a high- level noise stability headset sewn in the helmet that consists of a cable to contact to the push-to-talk switch from the ABCK set of any type.
The helmet is produced in two versions:
- summer TSH4-UL;
- winter TSH4-UZ.
Each variant is made of three sizes (I, II, III). A number of the helmet size corresponds to a size of a human head.
|Helmet size number||Head size, sm|
| Up to 56 inclusive|
The communication helmet keeps its serviceability under:
- ambient temperature from minus 50° C to +50° C;
- relative air humidity up to 98% at temperature not less than + 25° C;
- vibratory load in a range of 10 to 80 Hz with acceleration 29.4 m/s2 (3g);
- impact load with acceleration 735 m/s2 (75g) with pulse duration from 0.5 to 2.0 ms;
- effect of acoustic noise up to 135 dB;
- cyclic temperature changes from minus 60° C to +70° C;
- effect of hoar-frost and dew;
- conditions of low atmospheric pressure (6x104 ± 4x103) Pa ((450 ± 30) mm Hg);
- after atmospheric pressure impact 2.3 x 10-4 Pa (170mm Hg) at ambient temperature 223 K (minus 50°C), appropriate to air transporting.
MAIN ELECTICAL SPECIFICATIONS
|Description of the main parameters ||Norm upon Specifications|
|1. Verbal speech legibility under conditions of acoustic noise up to 135 dB, not less, %|
2. Noise suppression factor at frequency 1000Hz, not less, dB
3. Total noise stability of throat microphone under conditions
of acoustic noise up to 135 dB, not less, dB
4. Scalar impedance of a pair of throat microphone at frequency 1000 Hz, Ohm
5. Scalar impedance of a pair of telephones at frequency 1000 Hz, Ohm
6. Optimal level of voltage applied at headphones, V
7. Speech efficiency of throat microphones of the communication helmet, mV