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FREQUENCY CONTROL MODES OF ET 91 To learn more click on note! END to END Loss Measurement Group Delay Distortion Measurement Frequency Tracking with Sweep.

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Presentation on theme: "FREQUENCY CONTROL MODES OF ET 91 To learn more click on note! END to END Loss Measurement Group Delay Distortion Measurement Frequency Tracking with Sweep."— Presentation transcript:

1 FREQUENCY CONTROL MODES OF ET 91 To learn more click on note! END to END Loss Measurement Group Delay Distortion Measurement Frequency Tracking with Sweep Fr receiver = Carrier ± Fr transmitter Conventional Control Modes Special Receiver Control Modes Measurements with MTTS Frequency Modification with Cursor Keys Frequency Setting with Number Keys Fr receiver = Carrier ± Tone ELEKTR NIKA

2 Frequency Setting with Number Keys To set a new frequency use the NUMBER keys as usual. E.g Hz Notice: don’t touch the cursor keys ELEKTR NIKA

3 Frequency Modification with Cursor Keys The frequency STEP can be selected with the HORIZONTAL cursor keys The FREQUENCY can be modified with the VERTICAL cursor keys FREQU: kHz FREQU: kHz FREQU: kHz Notice: don’t touch the number keys Modification of frequency in 1Hz, 10 Hz 100 Hz etc steps. ELEKTR NIKA

4 Selectable ranges Frequency Tracking with Sweep ELEKTR NIKA

5 Receiver Frequency Setting in Carrier ± Tone Format Set carrierSet tone Select mode Test instructions of FDM systems often specify the test frequency in format: Carrier ± Channel ( Tone) Frequency. ET 91 provides the separate setting of carrier and tone frequencies and so: No frequency calculation is required! Final display format ELEKTR NIKA

6 Special Transmitter Tracking Mode During the test of FDM equipment often required a special transmitter tracking when: ■ audio frequency test signal is applied to the input of tested channel and ■ the modulated high frequency signal is measured In that case: Receiver Frequency (Rx)= Carrier ± Transmitter Frequency (Tx) In special transmitter tracking mode of ET 91 two parameter can be set: ■ the frequency of transmitter between 200Hz and 4 kHz in 1 Hz steps and ■ the carrier between 1kHz and 2400kHz in 1kHz steps The test frequency of level meter is automatically set ADVANTAGES: No frequency calculation is required ! In case of test series only one frequency setting is required ! ELEKTR NIKA

7 END to END Loss Measurements with MTTS MTTS METHOD: ■ The transmitter generates 35 test tones ■ The receiver measures the 35 test tones simultaneously ADVANTAGES: ■ No synchronisation is necessary between the two instruments ■ The measuring time is shorter than that of other methods ELEKTR NIKA

8 Group Delay Distortion Measurement with MTTS 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 ■ Group delay and signal level measurement at the same time ■ The measuring time is shorter than that of other methods ET 91 applies the multi tone test method described in Recommendation ITU-T O.81 Appendix I ELEKTR NIKA

9 THANK YOU FOR YOUR ATTENTION!


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