Standardized Positions; Positioning Terminology - BRUEL & KJAER HF HATS 5128 User Manual

4.3.4 Position
 A is measured off the end of the slide on the mounting bracket.  B and  C are recorded to the
nearest ½° using the markings provided on the swivel joints. In general the positioning accuracy
of Type 4606 when mounted on Type 5128 is ± 1 mm at ERP and ± 3 mm at MRP.
4.3.5

Standardized Positions

Type 4606 is easy to set up for standardized positions according to ITU-T Rec. P.64. The following
descriptions are valid for HATS mounted with Artificial Ear equipped with a pinna as specified by
ITU-T Rec. P.57.

Positioning Terminology

A Cartesian coordinate system is used to describe the standardized position by means of vectors.
Using ITU-T Rec. P.64 terminology, the coordinate system originates at CL and consists of three
axes called x , y
m m
with the mouth reference axis. The y
positive direction towards the right side of the head and the z
axis and y -axis with positive direction upwards. This head-fixed coordinate system corresponds
m
to the HATS reference plane (see Fig.4.13).
Fig.4.13
Diagram of vector
directions for head-
fixed coordinate
system
Similar to the head-fixed coordinate system, a Cartesian coordinate system must be defined for
the handset. This coordinate system originates from the handset ECRP and defines three axes:
x -axis is normal to the ear-cap plane with positive direction away from the earphone. The y
e
is the line of intersection of the handset symmetry plane with positive direction towards the
microphone. The z
ear. The z -axis points obliquely downwards.
e
With these two coordinate systems in mind, the standardized positions as defined in ITU-T Rec.
P.64 can be set up as described in the following.
Refer to ITU-T Rec. P.64 for the exact vector definitions of the standardized positions.
Handset Positioner for HATS Type 4606 Features and Functions
and z . The x -axis has positive direction into the mouth and coincides thereby
m m
-axis is horizontal, perpendicular to the x
m
A
x
e
ECRP
B
y
e
C
z
e
ECRP, Ear-cap Reference Point
-axis is normal to the other two axes and is for handsets applied to the right
e
CHAPTER 4
-axis is perpendicular to the x
m
z (up)
m
x (backw)
m
CL
y
m
CL, Centre of Lips
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-axis with
m
-
m
-axis
e