In traditional wireless conference systems, stability and reliability are key advantages, along with strong confidentiality and resistance to interference. However, these systems often require complex installation and maintenance, which can affect the overall aesthetics of the meeting space. This is especially true in environments where the layout of tables and chairs frequently changes or where mobile use across different rooms is necessary. As a result, wireless systems that eliminate the need for physical wiring have become increasingly appealing to users.
Wireless transmission technology was initially introduced into simultaneous interpretation systems within conference setups. Over time, wireless discussion systems have also gained traction. The reason for this is that simultaneous interpretation systems primarily focus on multi-person listening, without needing the more advanced features like "application," "priority," or multi-channel two-way communication that are common in discussion systems.
First, let's explore the wireless simultaneous interpretation system. Currently, there are three main types: low-frequency transmission, infrared transmission, and ultra-high frequency (UHF) transmission.
(1) Low-frequency transmission systems, also known as electromagnetic induction systems, operate by creating an audio electromagnetic field through a loop line within the listening area. A high-power amplifier sends this signal, and listeners use headphones connected to a coil and amplifier. While simple and cost-effective, these systems suffer from poor sound quality and stability. Their electromagnetic fields can penetrate walls, leading to security issues. However, this drawback can be turned into an advantage in settings like museums or large exhibition centers where multiple sub-sites need to use the same system.
(2) Infrared (IR) transmission systems use electromagnetic radiation beyond visible red light, operating at frequencies above 2 MHz. Since IR cannot pass through walls, it offers better confidentiality and resistance to interference. These systems provide stable performance and superior sound quality, making them a popular choice. Recently, infrared technology has shifted from Band II (45 kHz to 1 MHz) to Band IV (2 to 6 MHz), avoiding interference from energy-saving lamps. Band IV also offers wider frequency response, higher signal-to-noise ratio, and less channel interference, resulting in better audio clarity.
(3) UHF transmission systems, such as the GONSIN 2.4 GHz digital wireless system, use Direct Sequence Spread Spectrum (DSSS) encryption for secure communication. These systems can cover a range of 80–100 meters and support up to 16 voice channels. Compared to infrared systems, UHF systems offer non-directional reception, are not easily affected by energy-saving lamps, and have fewer environmental constraints, making them ideal for larger spaces.
Second, wireless conference discussion systems come in several forms:
(1) Hybrid wired-wireless systems were among the first to be introduced. They used wired connections between participants, chairpersons, and the main control unit, while wireless transmission was used between the main control unit and the audio mixer. These systems were cost-effective and stable but lacked flexibility and confidentiality, limiting their adoption.
(2) U-band wireless systems rely on independent wireless microphones for each participant and chairperson, operating on different frequencies. While the technology is mature and the structure is simple, these systems lack control functions, have limited capacity, and offer poor confidentiality. They are best suited for small meetings with budget constraints.
(3) G-band wireless systems, similar to the G-band simultaneous transmission systems, operate on the 2.4 GHz band and can support up to 200 units simultaneously. They use DSSS encryption and offer features like "application for speaking," "sound control," "priority," voting, and multilingual interpretation. Though more expensive, they are widely used in government and corporate settings due to their reliability and functionality.
(4) Infrared conference systems consist of a central control unit, transmitting/receiving units, and speaker units. Each speaker unit includes a microphone, speaker, and battery, communicating via infrared over a distance of up to 7 meters. These systems also support simultaneous interpretation and voting. Although considered a promising option, they still lag behind wired systems in terms of security, stability, and capacity.
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