HS-580 PCM Channel Analyzer
Why it is very important in Railway system?
The advent and augmentation of digital communication techniques has resulted not only in application of hi-tech methods but also in different performance compliance criteria as compared to the earlier systems. The A/D conversion and vice-versa used here entails complex quantizing, multiplexing and framing techniques, the quality of which governs the performance of the transmission equipments, PCM multiplexers and digital exchanges, which form the basic building block of present-day railway communication systems. The performance of the transmission equipments e. G. STM1, STM4 etc. Can be rated through BER and G. 821 monitoring but the last mile performance at the user interface level e. G. The analog VF parameters need additional quality check-UPS. This is because of umpteen technical reasons some of which are:
1. The channel performance degradation is a highly probable reality in the case of multiplexer related problem at the interface level even if link error performance is quite satisfactory.
2. For long networks, the omnibus channels used for Railway controls acquire significant noise level at each user nodes. This degrades overall S/N ratio which may corrupt the performance of highly selective VF band application e. G. DTMF signaling and data application using modems. In such cases, DTMF tones may not be decoded properly or data stream may be erroneous with garbage even if speech signal is through.
3. The users in the Railway environment are often co-located with HV induction environment, where the induced level of higher order harmonics of traction power is so high or imbalanced that even the isolation transformers frequently used by Railways cannot prevent the contamination of the circuits.
All these warrant a constant vigil on voice parameters not only at the time of commissioning, but also periodically as a part of maintenance in addition to line-up and fault finding. Typical requirements involve VF measurements and recording of PCM parameters like quantization noise and gain response.
The data communication (x. 25, group3 facsimile, v. 24 at PRS) using high-speed modems places significant demand on quality of these PCM channels. The end-to-end measurement of user channels throws light on the total network performance when a network cannot be put to off-line for adjudging link health. Last but not the least, the out of service measurement during various testing and breakdown maintenances is another area where voice channel analyzers find wide application.
The HS-580 is a world-class portable overall measuring instrument with many testing functions for PCM channel characteristics (both full-channel and half-channel), and error testing for E1 as well, based on multi-task OS of Win CE.
It can be used to measure PCM device, digital switch, carrier wave communication device, client's dispatching equipment, digital broadcasting station with voice channel interface and VoIP device, especially applicable to science research, manufacturing, engineering installation, check and acceptance as well as maintenance.
1. HS-580 PCM Channel Analyzer Basic Functions
Voice channel Characteristics testing
√ A-A: Level, Variation of gain with frequency, Variation of gain with input level, Total distortion including quantizing distortion, Idle channel noise, Crosstalk, Return loss, Longitudinal conversion loss, Longitudinal conversion transfer loss.
√ A-D, D-A, D-D: Level, Variation of gain with frequency, Variation of gain with input level, Total distortion including quantizing distortion, Idle channel noise, Crosstalk
2M (E1) frame and unframed BER testing, alarm detection and error analysis
Call set-up: Support on-hook, off-hook, dialing, ringing, and ringing supervise
Auto and manual mode available, on the auto mode, all or one or several of the above performance characteristics can be selected to measure
Support test of frequency spots sequence of equal step and customized frequency spots, and the number of spots is optional
Support selective frequency measuring on all frequency spot
Results are shown graphically, and can be compared with the built-in reference module to evaluate whether it passes or fails
Perfect indication of working state and alarm
Large storage capacity of results and measuring
Configurations, up to 100 groups
Available in remote control via USB and Ethernet interface, to meet the need of different control modes
Results can be uploaded to PC, so as to be analyzed, assembled, filed and printed via TestManager PRO software
2. HS-580 PCM Channel Analyzer Main Features
Overall functions, satisfy users' measuring requirements
Integrated with tone oscillator, Selective Frequency Meter, BER tester and Call Generation, more PCM channel characteristics can be measured one time
5.7 inches 640X480 high-resolution colorful LCD display
Flexible control modes, supporting touch operation, key-stroke operation and expanded mouse operation
Convenient Windows style, easy to operate
Built-in call set-up circuit, can set up testing channel directly by dialing on the tester without the help of other telephone
Built-in generator and receiver, analog input and output interfaces are separately with ICT and OGT. Interfaces can be directly tested, including 2/4W E&M, MDR, LGE, FXO, LGS and FXS
Built-in balanced bridge and reflecting bridge, Return loss, Longitudinal conversion loss and Longitudinal conversion transfer loss can be measured by one tester
Built-in test mode can be defined by clients, efficiently satisfying testing standard definition of different products
Remote control signaling group is available, so as to secondarily develop under different conditions by clients
Embedded software can be upgraded online and protect the client's investment