Baseband Signal Processor

23

MX829 PRELIMINARY INFORMATION

© 1998 MX

•COM Inc.

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Fax: 336 744-5054

Doc. # 20480160.004

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Notes

Min.

Typ.

Max.

Units

MSK Receiver

Signal Input Dynamic Range (SNR = 50dB)

10, 11

100

230

1000

Bit Error Rate

SNR = 12dB at 1200 Baud

11

2.5

SNR = 12dB at 2400 Baud

11

1.5

SNR = 20dB at 1200/2400 Baud

11

1.0

Receiver Synchronization (SNR = 12dB)

12

Probability of Bit 16 being correct

0.995

%

Carrier Detect

Sensitivity

12, 13

150

Probability of Carrier Detection

After Bit 16 (SNR = 12dB)

0.995

%

0.05

%

Miscellaneous Impedance

FILTER OUT

600

Ω

Tx Audio Input (MIC) (at 100Hz)

10

M

Ω

Xtal/Clock Input

'High' pulse width

4

40

ns

'Low' pulse width

4

40

ns

Input Impedance (at 100Hz)

10

M

Ω

20

dB

Operating Characteristics Notes:

1.

Signal levels are proportional to VDD.

2.

Not including any current drawn from the modem pins by external circuitry.

A. Powersaved = all functions disabled.

B. Tx or Rx = device configured into any half-duplex operating mode.

3.

Small signal impedance. A minimum load resistance of 6k

Ω is suggested.

4.

Timing for an external input to the XTAL/CLOCK pin.

5.

Between MIC or AMP1 inputs to Modulator and Audio outputs, see Figure 12 and Figure 13.

6.

It is recommended that these output levels are used to produce 60% or 100% deviation in the transmitter.

7.

With the Tx Audio input level 20dB above the level required to produce 0dB at the Output Drives.

8.

With output gains set to 0dB.

9.

IRQ pin.

10. See Figure 16 (variation of BER with Input Signal Level).

11. SNR = Signal to Noise Ratio in the Bit Rate Bandwidth.

12. For a "10101010101 ...01" pattern.

13. Measured with a 150mVRMS input signal (no noise).

14. dBp represents a psophometrically weighted measurement.