B&K 230 - SECTION I GENERAL DESCRIPTION; 1.1 Description of Model 230 and Mastoid; 1.2 Model 230 Technical Specifications

SECTION I
GENERAL DESCRIPTION
1.1 Description
The B & K Model 230 Calibration Control Oscillator and the B & K
Model
4931 Artificial Mastoid Calibrator are used together to calibrate
the frequency response and force sensitivity of the B & K Model 4930
Artificial Mastoid. The Model 230 Calibration Control Oscillator has
eleven pushbutton-selected variable level test tones in the range from
125 to 8000 Hz, in accordance with the ANSI 1) and IEC
2
) audiometer
test standards. The calibration control oscillator also contains
the signal conditioners for transducer signals from the Artificial
Mastoid and the force and acceleration outputs of the Impedance Head
Model
8000. A mass compensation circuit is included to cancel out the
residual mass below the force sensing element. Mass compensation at
1000 Hz reduces the effect of residual mass to below 0.2 % of the true
force signal level at all test tone frequencies. An external rms volt-
meter is used with the Model 230 to read both the force applied and
the mastoid output.
1.2 Specifications
Oscillator
Output Frequencies:
Frequency Accuracy:
Output Level (Filter Out) :
Output Impedance:
Distortion:
Filter Characteristics:
125, 250, 500, 750,
2000, 3000, 4000,
+~
1000,
6000,
1.3 V rms into 6 Ohm load
10 Ohms
2% at 0.1 V rms
1500,
8000 Hz.
High pass, 0.5 dB at 3 kHz and
-10 dB at 125 Hz.
1) - ANSI Stand ar d S3.13-1972: An Artificial Head-Bone for the calibration of
Audiometer Bone Vibrators.
2) - IEC Draft Document 29C (Cent r al Office)9.