Yokohama National University

Yokohama National University

Models installed
two PJP-EC200s
Date of installation
November 2009
Basic configuration
Two-Way High-Vision Distance Lecture System in which a PJP-EC200 works in tandem with a TV conferencing system, and which also incorporates laser pointer highlighting devices and cameras.
Overview of Yokohama National University

Yokohama National University is developing its educational and research activities under the banner of practicality (stressing these activities' connection to society at large), with a focus on the concepts of innovation (enthusiastically encouraging new experimentation), inclusivity (opening its doors wide to the general public), and internationalism (promoting overseas exchanges). Now, more than 130 years after its foundation, the university is devising a highly original fusion of the arts and sciences, in fulfillment of its aim of becoming a distinguished center for practical scholarship.

Implementing a two-way high-vision distance lecture system using the outstanding functionality of the PJP-EC200 echo canceller

Background to the adoption of the PJP-EC200

Constructing a revolutionary two-way distance lecture system in cooperation with other universities

  • Cooperation from an early stage with universities both in Japan and overseas
  • Shared video, PC screen, and laser pointer
  • Easy two-way conversation also a requirement

With its ideals of inclusivity and internationalism, Yokohama National University was quick to engage in cooperation with other universities, both in Japan and overseas. On the domestic front, since 2004 the university has been cooperating with Yokohama City University Graduate School of Medicine and its affiliated hospital in the construction of a system to enable students to attend distance lectures for the study of welfare and medical treatment. Starting in 2009, the university established an educational program for environmental leaders in developing nations in the form of distance lectures shared with the University of Nairobi, Lampung University in Indonesia, and the University of Science, Malaysia. This was made possible by the Two-Way High-Vision Distance Lecture System, in whose development the university played a key role. The features of this system are that clear video images of the lecturer and the audience are visible in both lecture halls, and that the presentation displayed on the lecturer's PC and the highlighting carried out using the lecturer's laser pointer are shared between the venues in real time. Since it enables easy two-way conversation, this revolutionary system has also facilitated cooperation between the universities.

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Reasons why a PJP model was selected

It solves voice issues that are characteristic of large-scale distance lectures, such as complex echo.

  • More stringent requirements than for ordinary remote conferencing
  • High-performance adaptive echo canceller
  • Able to work automatically with portable handheld microphones

Since a distance lecture system working between multiple universities requires bidirectional communication of video, PC screen, laser pointer, and audio, the system had to meet more stringent requirements than ordinary remote conferencing systems. In the specific case of audio, this system generates much more complex echo and howling than ordinary remote conferencing systems, since it has to amplify the lecturer's voice in the lecture hall, and mix and amplify the voices of questioners in the remote lecture hall. As a result of this, on the university's initial system staff members were faced with the inconvenience of manually performing operations such as turning microphones on and off. The Yamaha PJP-EC200 solves these acoustic problems, which are characteristic of distance lectures. Thanks to its extremely high-performance adaptive echo cancellers, this system not only allows easy two-way conversation, but also enables smooth remote conferencing by tracking the lecturer as he or she walks around with a handheld microphone, and adjusting accordingly.

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Results of the adoption of the PJP

The PJP-EC200?supporting audio signal transfer in smooth-running distance lecture systems

  • Useful for large-scale events and instruction
  • Solves the problems of echo and howling
  • Destined to become a standard component in audio systems

The university currently has Two-Way High-Vision Distance Lecture Systems incorporating PJP-EC200 units installed in two locations?the Central Library and the Education and Culture Hall. These are both used for large-scale events and instruction. This is an extremely high-level distance lecture system: at the same time that it is amplifying the lecturer's voice within the hall, it is also transmitting both video and audio via a TV conferencing system and sharing the PC screen and the laser pointer movement with other universities in multiple locations, as well as recording all this data. The voice-related problems such as echo and howling that are generated by this complex system are all solved by the PJP-EC200. As levels of cooperation with other universities increase, the university is considering further developing and standardizing its existing Two-Way High-Vision Distance Lecture System in the future, and making a component based on the PJP-EC200 the centerpiece of the voice system.

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Resolving tricky voice problems, such as complex echo and howling, in TV conference systems and configurations involving mixers, microphones, and speakers. This system achieves smooth two-way conversation between multiple locations.

The customer's voice


Hiroshi Arisawa
Doctor of Engineering

Professor at the Graduate School of Environment and Information Sciences, Yokohama National University

The PJP-EC200's echo-cancelling functionality was needed for this large-scale distance lecture system. It is expected that in the future this device will be the core component of the acoustic segment of this product.

Essentially, the two-way distance lecture system installed at Yokohama National University boasts two major characteristics. The first is that a large screen in each location synchronously displays video of the lecturer as well as the screen on his or her PC showing his or her presentation, and the movement of the laser pointer on screen. Second, the system enables the amplified voices of both the lecturer and the questioners to be heard in each location, and achieves trouble-free two-way communication without any echo or howling. The Yamaha PJP-EC200 was the ideal echo-cancelling device for the voice-system component of this system. It was the only such product that could achieve this level of performance at a reasonable price. This could be described as the crowning glory of Yamaha acoustic technology. Although further development of the current distance lecture system and standardization of all its components (for imaging, highlighting, recording, and sound) is under consideration, in the acoustic-device category, the PJP-EC200 would seem to be the strongest candidate. It is extremely important that university lectures have a sense of realism and we anticipate that Yamaha will further refine the functions of the PJP-EC200.(Professor Arisawa)

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Features of the Two-Way High-Vision Distance Lecture System

A revolutionary two-way distance lecture/distance conferencing system for use between universities in Japan and overseas

  • The system consists of a high-vision conferencing system, support devices for two-way highlighting and distance lectures, and consumer-level cameras.
  • XGA-resolution screen images are captured from the PC displaying the presentation and transmitted from the lecturer's location to the audience's location. Simultaneous highlighting using a laser pointer is possible in both directions (both the lecturer and the audience members see the same screen image, and can highlight using the pointer while looking at the other party).
  • For overseas locations where the Internet communications capacity is extremely limited, the system adjusts the image quality and frame rate, and provides a back-up method known as storage synchronization.
  • The PJP-EC200 works with TV conference systems and configurations involving mixers, microphones, and speakers, and resolves voice problems such as echo and howling, enabling smooth two-way conversation.

No. 1 location of PJP-EC200?Hall of Education and Culture

No. 2 location of PJP-EC200?Central Library

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Features of the PJP-EC200

  1. Specialized echo canceller to which a variety of different microphones and speakers can be connectedThe PJP-EC200 can be used in conference or assembly rooms for ten or more people, to which previous PJP Series models were unsuited. It can also easily cope with irregular conference room layouts, such as a U-shaped or O-shaped desk configuration or a classroom arrangement.
  2. High-performance adaptive echo cancellers on two channelsThe PJP-EC200 improves upon the acoustic technology that has been developed on the PJP Series. It is equipped with adaptive echo cancellers that automatically adjust parameters to their optimum values for a variety of environments and hardware configurations. It also boasts a two-channel mixing function which allows microphones to be connected to it directly, without the need for a mixer.
  3. Voice adjustment system that makes use of established Yamaha technologyThe PJP-EC200 is also equipped with a feedback suppressor-type howling canceller for when the system is used in a large conference or assembly hall, to enable it to cope with the PA system that is being used to output the lecturer's voice (in the hall where the lecture is actually being delivered). The howling canceller can also be used when speaker amplification is required for the lecturer at a distance seminar, or simply as a standalone howling canceller. The device is also equipped with noise reduction and can thus reduce noise from the projectors or air-conditioning, enabling trouble-free sound pick-up and playback.

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Product Lineup

PJP-EC200

PJP-EC200
[Conference Echo Cancellers]

Powerful echo cancelling in settings from small to large conference rooms.

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