Dual SPM Detector

Page 10 of 16

MX641 Preliminary Information

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ã2001 MX-COM, Inc.

www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054

Doc. # 20480115.004

4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA

All trademarks and service marks are held by their respective companies.

4.3.1.2

German FTZ Specification (16kHz)

The FTZ system has a Must Decode level of -21dB (ref.) and a Must-Not Decode level of -27dB (ref.).

Reference to

Table 4 shows that Bandpass Filter Gain settings of 5dB, 6dB or 7dB will enable an MX641 channel to meet

this level specification. Figure 5 illustrates the range of these various settings.

To meet the German FTZ specification, the input data (D5 to D0) must be:

0 0 1 0 1

0

5.0dB

or

0 0 1 1 0

0

6.0dB

or

0 0 1 1 1

0

7.0dB

Note:

1.

By selecting the middle setting, the greatest noise immunity is achieved.

MUST

DECODE

-21dB(ref.)

-27dB(ref.)

MUST-NOT

DECODE

WILL

DECODE

WILL-NOT

DECODE

-21.9

-23.2

5.0dB

-24.5

-22.9

-24.2

6.0dB

-25.5

-23.9

-25.2

7.0dB

-26.5

Figure 5: German Specification - Possible Settings

4.3.1.3

French Specification (12kHz)

This system has a Must Decode level of -17.36dB (ref.) and a Must-Not Decode level of -23.8dB (ref.).

Reference to

Table 4 shows that Bandpass Filter Gain settings of 2dB, 3dB or 4dB will enable an MX641 channel to meet

this level specification. Figure 6 illustrates the range of these various settings.

To meet the French SPM specification, the input data (D5 to D0) must be:

0 0 0 1 0

1

2.0dB

or

0 0 0 1 1

1

3.0dB

or

0 0 1 0 0

1

4.0dB

Note:

1.

By selecting the middle setting, the greatest noise immunity is achieved.

MUST

DECODE

WILL

DECODE

WILL-NOT

DECODE

-17.36dB(ref.)

-23.8dB(ref.)

MUST-NOT

DECODE

-18.2

-19.5

2.0dB

-20.8

-19.2

-20.5

3.0dB

-21.8

-20.2

-21.5

4.0dB

-22.8

Figure 6: French Specifications - Possible Settings