Variable Length Curve Flags

The first two words of each curve frame contains the curve frame flags (flags 0 and 1). These flags contain information on the curve type, details about how the curve was measured or calculated, and other important data. To decipher the curve frame flags, the curve frame format must first be determined.

Curve Frame Format (Flag 0, Bits 10-12)

Bits 10-12 of flag 0 contain the curve frame format:

Value

Description

Data Points

4

Variable Length Curve

Variable

Note: Number of points kept in header word 5(was peak).

Data Length

The number of data points in a Variable Length curve is in header word 5(highest value)

 

Source Type (Flag 1 Bit 6, Flag 1 Bit 4, Flag 1 Bit 3, Flag 0 Bit 0)

These four non-contiguous bits of data contain the source type used in the curve.

Value

Description

0

Pure-tone

1

Composite

2

Fast pure-tone with warble (FP35 only)

5

Composite chirp

8

Pure tone burst/pulse

9

Digital speech

11

Distortion chirp

15

Unknown source

Distortion Type (Flag 0, Bits 1-2)

The first two bits of data of flag 0 contain the distortion type of the curve. Harmonic distortion is only measured with a pure-tone source type.

Value

Description

0

No distortion measured

1

2nd harmonic distortion

2

3rd harmonic distortion

3

Total harmonic distortion

Correction Factors (Flag 1 Bit 7, Flag 1 Bit 0, Flag 0 Bit 3)

These three non-contiguous bits of data represent the software correction factors used with the curve.

Value

Description

0

No corrections

2

OES corrections

4

CIC corrections

Reference microphone status (Flag 0, Bit 4)

Bit 4 of flag 0 indicates whether the reference microphone was enabled during the measurement. The FP35 may use a reference microphone for both coupler and real-ear measurements. The 7000 will only use a reference microphone for real-ear measurements.

Value

Description

0

Reference microphone disabled

1

Reference microphone enabled

Smoothing status (Flag 0, Bit 5)

Bit 5 of flag 0 indicates whether the smoothing status of the measurement. The FP35 may use a smoothing for both coupler and real-ear measurements. The 7000 will only use smoothing for real-ear measurements.

Value

Description

0

Smoothing disabled

1

Smoothing enabled

Transducer (Flag 0, Bits 6-7)

Bits 6-7 of flag 0 indicate whether the transducer used during the measurement.

Value

Description

0

Sound chamber

1

Telecoil

2

Sound field speaker

3

Earphone

Filtering (Flag 0, Bits 8-9)

Bits 8-9 of flag 0 indicate whether the source signal has been filtered (speech weighted), and whether the measurement data is accounting for that filter or giving raw measurement data (usually an indication of whether the measurement data is in gain or output).

Value

Description

0

No filtering

2

Source filtered, measurement data raw

3

Source filtered, measurement data filtered

Leveling status (Flag 0, Bit 13)

Bit 13 of flag 0 indicates whether the source is leveled. "Semi-leveled" is considered "leveled" in the curve frame.

Value

Description

0

Not leveled

1

Leveled

Gain status (Flag 0 Bit 14)

Bit 14 of flag 0 indicates whether the measurement curve is Gain or SPL.

Value

Description

0

SPL (output)

1

Gain (output minus input)

Curve Reference (Flag 0 Bit 15, Flag 1 Bit 5)

Bit 15 of flag 0 and bit 5 of flag 1 indicates if the curve is measured, computed, average, or predicted.

Value

Description

0

Measured

1

Computed/difference

2

Average

3

Predicted

Modification Status (Flag 1 Bit 2)

Bit 2 of flag 1 indicates whether the curve has been modified after it was measured or calculated..

Value

Description

0

Not modified

1

Modified

Curve Type Identifier (Flag 1, Bits 8-11)

Bits 8-11 of flag 1 contain the curve type identifier:

Value

Description

0

Response curve

1

Real-ear unaided gain (REUG)

2

Real-ear aided gain (REAG)

4

Real-ear aided gain (REIG)

5

Leveling curve

7

Battery curve

8

Target curve

9

Audiogram curve

10

Polar curve(dB vs angle)

Curve Sub-type (Flag 1, Bit 12-15)

The curve sub-type values vary depending upon the curve frame format and the curve type identifier. Curve types Response (0), REUG (1), REAG (2), REIG (4), Polar(10) have the following sub-types:

Value

Description

0

Unknown

1

Flat weighted

2

ANSI weighting

3

ICRA weighting

4

UWO child LTASS

5

Cox & Moore adult LTASS

7

ANSI 92 weighting

8

X-Axis list

9

Measurement Delay list

 Curve types Targets (8) have the following sub-types:

Value

Description

0

NAL-R

1

POGO

2

Berger

3

1/3 Gain

4

1/2 Gain

5

2/3 Gain

6

DSL linear

7

DSL WDRC

8

NAL-NL1

14

Other

15

Direct

 

Original Flag Inventory:

Flag 0:  Bit 0(Source type), Bits 1-2(Distortion type), Bit 3(Correction factors), Bit 4(Ref Mic), Bit 5(Smoothing), Bits 6-7(Transducer), Bits 8-9(Filtering),

Bits 10-12(Curve frame format), Bit 13(Leveling status), Bit 14(Gain status), Bit 15(Curve reference).

 

Flag 1:  Bit 0(Correction factors), Bit 1(UNDEFINED), Bit 2(Modified), Bits 3-4(Source type), Bit 5(Curve reference), Bit 6(Source type), Bit 7(Correction factors),

Bits 8-11(Curve type ID), Bits 12-15(Curve subtype).

 

 

New Flag Inventory:

No changes.