12
Testing FM Systems with FONIX 6500-CX Analyzers
1.2.2 Test FM microphone with typical input — EFM80
1. Set up the FM system according to the FM system setup in Section 1.1.3.
2. Use
[
∧
] to adjust the signal level to 80 dB SPL.
3.
This curve will be referred to as the Electroacoustic FM Response or EFM80. (Since
the current running curve is always stored as CRV 1 in the Multi-Curve buffer, there
is no need to press [FREEZE] and [START] to save the curve as you did in Section
1.2.1.)
4. To view the EFM80 and EHA65 on the same screen requires the Multi-Curve Option:
a. Press
[MULTI].
b. Highlight
MULTIPLE
CURVES.
c. Press
[START].
d. If necessary, use [<, >] to display CRV 1 in the first slot. This curve is EFM80.
e. Use
[
∨
] to select the second slot.
f. If necessary, use [<, >] to display CRV 2 in the second slot. This curve is EHA65.
See Figure 1.2.2.
If you don’t have the Multi-Curve Option, press [CRT] to print out EFM80 and com-
pare it to EHA65.
Figure 1.2.2
Comparison of EHA65 (CRV2), the hearing aid response at 65 dB
SPL and EFM80 (CRV1), the FM response at 80 dB SPL
