Frye FONIX FP40D - Manual (Page 30)

22 FONIX FP40 Portable Hearing Aid Analyzer
2.4.1.1 Pure-tone settings
There are several different settings available in the General Setup Menu for pure-tone signals. Here
is an explanation of those settings.
RESET FREQ: The frequency the analyzer returns to when RESET is pressed.
NOISE REDUC: The amount of noise reduction used in pure-tone measurements. See Section
2.4.1.2.
SETTL. TIME: The amount of time each tone is presented before the measurement is made. See
Section 2.4.1.3.
AVG FREQS: The frequencies used with the AVG function that averages the responses of three dif-
ferent frequencies. Each frequency set is represented on the screen by the highest frequency in the
set. The sets are:
HFA (High Frequency Average) - 1000, 1600, 2500
SPA (Special Purpose Aids) - 800, 1250, 2000
SPA - 1250, 2000, 3150
“ “ - 1600, 2500, 4000
“ “ - 2000, 3150, 5000
IEC– (HAIC) - 500, 1000, 2000
DISTORTION: The type of harmonic distortion display.
DIST TYPE: Type of harmonic distortion tested. See Section 2.4.1.4.
SWEEP TYPE: Type of pure-tone sweep used in measurements. Choose NORMAL, FAST, or SHORT.
2.4.1.2 Noise Reduction
Noise reduction is used in noisy testing environments. Pure-tone noise reduction takes several mea-
surements at each frequency and averages those measurements together. You can select the amount
of measurements and averaging in the General Setup Menu, in the PURETONE SETTINGS section,
under NOISE REDUC.
Larger noise reduction numbers lead to smoother curves but increase the amount of time it takes to
complete a pure-tone sweep.
2.4.1.3 Settling Time
When you are measuring with pure-tone sweeps, you are offered a choice of settling times. By this
we mean that the tone source will be continued for a chosen amount of time before the measure-
ment is made. This choice is allowed because some hearing aid circuits take a longer time than oth-
ers to adjust to changes in amplitude or frequency. If the measurement is made too quickly, an arti-
fact in testing will be created. If the measurement takes too long, the test is longer than necessary.