Edgetech 2000-TVD, User Hardware Manual

Page: 34 / 111

2-6 2.0: SPECIFICATIONS
2000-TVD COMBINED SONAR 0017424_REV_B
SPECIFICATION VALUE
Pulse bandwidth/pulse length:
0.5–8.0 kHz/5 ms
0.5–2.7 kHz/40 ms
0.5–6.0 kHz/20 ms
0.5–4.5 kHz/50 ms
0.5–6.0 kHz/9 ms
0.5–6.0 kHz/18 ms
0.5–7.2 kHz/30 ms
0.7–12.0 kHz/20 ms
2.0–12.0 kHz/20 ms
Vertical resolution: a
19 cm (1–5.0 kHz)
12 cm (1.5–7.5 kHz)
8 cm (2–12 kHz)
Penetration in coarse and calcareous
sand:
b
20 m
Penetration in soft clay: b 200 m
Beam width: c
41°, 0.5–5 kHz
32°, 1–6 kHz
24°, 1.5–7.5 kHz
16°, 2–12 kHz
Optimum towfish pitch/roll:
<16°, 0.5–5 kHz
<13°, 1–6 kHz
<10°, 2–8 kHz
<8°, 2–10 kHz
<7°, 2–12 kHz
Transmitters:
2
Table 2-3: 2000-TVD Towfish Specifications
a. Vertical resolution is the smallest distinguishable distance between the peaks of two reflections that can be
displayed on the screen as separate reflectors. Sound energy is reflected to the sonar system when the transmitted
pulse encounters a change in density. The resolution of a sonar system is measured by its ability to distinguish
between two adjacent targets. The vertical resolution is dependent on the transmitted chirp pulse bandwidth. It
is theoretically calculated by the product of the transmitted pulse length (inverse of the bandwidth) and half the
speed of sound in water (approximately 750 m/s). For example, a full bandwidth pulse from an SB-424 Towfish has
a vertical resolution of 3.75 cm (1/20,000 x 750).
b. The value for sub-bottom penetration is the maximum distance beneath the sea floor that a step change of 10%
in density can be seen on the sub-bottom display. This assumes that the sediment is gas free (no organic materials),
that the lowest frequency of the pulse spectrum is transmitted and that the vehicle is within 5 meters of the seabed
(range for maximum penetration). Lower frequencies reduce attenuation (absorption of sound). Towing the