详细资料：
The Error Rate Measuring Equipment ME448A is a small, easy-to-operate measuring instrument designed to measure binary errors by bit-by-bit detection in digital systems over 1 kbit/s to 50 Mbit/s (covered PCM hierarchy from 1st to 3rd order).
The ME448A is intended for used in maintenance, commissioning, product testing, field trial of digital transmission terminal and link equipment.
It is also useful for testing digital radio systems, digital line systems, digital multiplex and optical fiber equipment, both satellite and terrestrial.
The ME448A consists of two parts: the sender unit and the receiver unit. Consequently a single test set alone is capable of end-to-end measurements of digital systems and thus more economical. Of course, it is also capable of loop-back testing. The send unit transmits an M-sequence (maximum length sequence) pseudo-random pattern which nature is similar to that of the pattern of actual PCM signals.
The receive unit receives the signal from a system under measurement, detects error pulses, counts their number and displays it.
The result of the error rate measurement is displayed by the digital display for direct readout of the error rate. Furthermore, in conjunction with a Digital Printer MH047A, the ME448A permits recording of measured results with the time of measurements for continuous measurement for a long period of time.
Features
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CCITT compatible
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Operating range: 1 kbit/s to 50Mbit/s
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Loop-back and end-to-end measurements
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Sending unit, internal clock crystal oscillator: maximum four frequencies installed
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Receiving unit, bipolar clock recovery: maximum three frequencies installed
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Bipolar and unipolar system measurements
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Bi polar - maximum four outputs (two outputs standards) Unipolar - pattern: four outputs clock: two outputs
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Measuring pattern: Psuedo-random pattern maximum length 215 - 1or 223 - 1bits
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Measuring codes: AMI, HDB3
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Error rate measurement and error pulse counting by detecting binary bit errors or code violation errors (option)
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Recorder output/Printer output
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Pseudo-bit error addition for self testing
