Document ID: chunk:federal_register_of_legislation:F2024L01024:front:0:p186
Version: federal_register_of_legislation:F2024L01024
Segment Type: other
Provision Reference: 
Character Range: 539575–542708

exceeding 35 m;
                       N.B.: For inertial heading systems, see 7A003.c.
6. A. 001. a. 2. e. Bottom or bay cable systems, having any of the following:
1. Incorporating hydrophones specified by 6A001.a.2.a.; or
2. Incorporating multiplexed hydrophone group signal modules having all of the following characteristics:
a. Designed to operate at depths exceeding 35 m or having an adjustable or removable depth sensing device in order to operate at depths exceeding 35 m; and
b. Capable of being operationally interchanged with towed acoustic hydrophone array modules;
                      3. Incorporating accelerometer‑based hydro‑acoustic sensors specified by 6A001.a.2.g.;
6. A. 001. a. 2. f. Processing equipment, specially designed for bottom or bay cable systems, having "user‑accessible programmability" and time or frequency domain processing and correlation, including spectral analysis, digital filtering and beamforming using Fast Fourier or other transforms or processes;
6. A. 001. a. 2. g. Accelerometer‑based hydro‑acoustic sensors having all of the following:
                      1. Composed of three accelerometers arranged along three distinct axes;
                      2. Having an overall 'acceleration sensitivity' better than 48 dB (reference 1,000 mV rms per 1g);
                      3. Designed to operate at depths greater than 35 meters; and
                      4. Operating frequency below 20 kHz.
Note: 6A001.a.2.g. does not apply to particle velocity sensors or geophones.
Technical Notes:
1. For the purposes of 6A001.a.2.g., accelerometer-based hydroacoustic sensors are also known as vector sensors.
2. For the purposes of 6A001.a.2.g.2., 'acceleration sensitivity' is defined as twenty times the logarithm to the base 10 of the ratio of rms output voltage to a 1 V rms reference, when the hydro‑acoustic sensor, without a preamplifier, is placed in a plane wave acoustic field with an rms acceleration of 1 g (i.e., 9.81 m/s2).
6. A. 001. b. Correlation‑velocity and doppler‑velocity sonar log equipment, designed to measure the horizontal speed of the equipment carrier relative to the sea bed, as follows:
1. Correlation‑velocity sonar log equipment having any of the following characteristics:
a. Designed to operate at distances between the carrier and the sea bed exceeding 500 m; or
b. Having speed "accuracy" better than 1% of speed;
2. Doppler‑velocity sonar log equipment having speed "accuracy" better than 1% of speed.
Note 1: 6A001.b. does not apply to depth sounders limited to any of the following:
                   a. Measuring the depth of water;
                   b. Measuring the distance of submerged or buried objects; or
                   c. Fish finding.
Note 2: 6A001.b. does not apply to equipment specially designed for installation on surface vessels.
6. A. 001. c. Not used.
 OPTICAL SENSORS
6. A. 002. Optical sensors or equipment and components therefor, as follows:
N.B.: SEE ALSO 6A102.
6. A. 002. a. Optical detectors as follows:
1. "Space‑qualified" solid‑state detectors as follows:
Note: For the purpose of 6A002.a.1., solid‑state detectors