1. Application Notes for Frequency Division Multiplex System Testing with ET 91 To learn more click on note! Basic, Super & Master Group Voice Frequency Noise END to END Measurements Pilot Level Measurement Noise Level Measurement Level Measurement in Tracking Mode Impulsive Noise Measurement Psophometric Noise Measurement Frequency Response Test with MTTS Automatic Master Slave Channel Test Group Delay Distortion Micro Interruption Analysis Jitter and Frequency Difference ELEKTR NIKA

2. Signal Level Measurement in Transmitter Tracking Mode of ET 91 Changing the transmitter frequency (Tx) the receiver automatically follows the change according to the selected rule: Rx=CARRIER+Tx or CARRIER-Tx ELEKTR NIKA

3. Noise Level Measurement at Master Group with ET 91 ELEKTR NIKA

4. Pilot Level Measurement at Super Group with ET 91 ELEKTR NIKA

5. Pilot Frequency Allocation Schematics ELEKTR NIKA

6. Psophometric Noise Level Measurement with ET 91 Display format up to 1 min Display format over 1 min ELEKTR NIKA

7. Impulsive Noise Measurement with ET 91 Display format up to 30 sec Display format over 30 sec An impulse is counted when the received noise signal exceeds a preset threshold for more than 500 ns ELEKTR NIKA

8. Automatic Channel Test in Master Slave Mode of ET 91 ▼ Click here to see detailed results ELEKTR NIKA

9. All the test results are available also in numeric format and they can be transferred to PC via USB interface. Test Result of Automatic Tone Channel Test ELEKTR NIKA

10. Frequency Response Test of ET 91 with MTTS Method MTTS METHOD: The transmitter generates 36 test tones ■ Frequency range: 100 to 3600 Hz ■ Frequency step: 100 Hz ■ Level: -20 dBm / frequency The receiver measures the 36 test tones simultaneously ADVANTAGES: ■ No synchronisation is necessary between the two instruments ■ The measuring time is shorter than that of other methods ELEKTR NIKA

11. Micro Interruption Analysis with ET 91 An interruption is detected when the level of test tone drops below a designated threshold for more than 0,6 ms. The detected interruptions are included into five categories by duration ▼ Click here to see the test results In graphic and numeric forms ELEKTR NIKA

12. Detailed Results of Micro Interruption Analysis All the test results are available also in numeric form and they can be transferred to PC via USB interface. ELEKTR NIKA

13. Group Delay Distortion Measurement with ET 91 ET 91 applies the multi tone test method described in Recommendation ITU-T O.81 Appendix I The transmitter generates 36 test tones ■ Frequency range: 100 to 3600 Hz ■ Frequency step: 100 Hz ■ Level: -20 dBm / frequency The receiver measures the 36 test tones simultaneously ELEKTR NIKA

14. Phase Jitter and Frequency Difference Measurement ET 91 performs jitter and frequency error measurements simultaneously according to Recommendation ITU-T O.91 That measurement needs two instruments connected to the ends of the tested line. ■ One of them transmits jitter free quartz accurate 1020 Hz test tone ■ The other one receives and evaluates it ELEKTR NIKA

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