CST2013: 0D / HAC (Hearing Aid Compatibility of Mobile Phone)

Post Processing: Result TemplatesTemplate Based Post Processing

HAC evaluates the E- and H-nearfields of a radiating device, typically a mobile phone, in a 2D plane parallel to the front cover of the device, centered to the speaker point.

Pre-requisite to run the result template is therefore the definition of both E- and H-field monitores for the frequencies of interest. The speaker point needs to be marked with a working coordinate system (WCS) with the origin in the speaker point and the u-v-plane parallel to the front cover. The WCS needs to be stored (“WCS -> Store Current WCS…”)

According to the specification of ANSI C63.19 a 50mm x 50mm area is spanned in 15 mm distance from the speaker point and subdivided in nine sub-grids. By unchecking the ANSI C63.19 checkbox user-defined areas can be considered. Also the resolution of the field evaluation can be specified (default: 1mm).

Power Scaling:

It can be chosen if the power is scaled to port power or to accepted (radiated) power.

AWF:

Depending on the transmission protocol an “Articulation Weighting Factor, AWF” gets defined. For CDMA, TDMA (50 Hz), UMTS (WCDMA) and TDMA (22Hz and 11 Hz) the AWF equals 0 dB, for GSM (217) it is -5dB.

“Abs value = simple square sum”:

Instead of the real field vector maximum the absolute value gets computed from “Emax = Sqr(|Ex max|^2 + |Ey max|^2 + |Ez max|^2). This value is always larger then the real amplitude, but may represent the way typical measurement equipment is working.

Logfile:

The essential information of the HAC evaluation is shown in the logfile. All nine E- and H-fild values are shown in original and scaled form. Additionally the HAC category of each sub-grid value and those values that get excluded according ANSI C63.19. At the bottom the final HAC category is shown together with the global exclusion scheme:

? T: Both E- and H are considered (“Taken”)

? E: E-Field got excluded

? H: H-field got excluded

? A: Both (“All”) are excluded

Show E / Show H:

The E- or H-field in the plane of HAC evaluation is visualized. The plots get scaled to display both the minimum mand maximum value within the domain of evaluation (“scan area”). Additionally the nine sub-grids are displayed.