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Bluetooth® vs. VConnect™
Introduction
Both Bluetooth® and VConnectTM are designed to
operate in an unlicensed radio band, called the ISM band,
with the central frequency of 2.45GHz. This is a very
crowded frequency band and one of the technical challenges
is to develop a method to avoid interference and co-exist
with other devices operating in the same frequency band. A
common device in this ISM band is the Wi-Fi (802.11b
standard) wireless LAN router for PCs and notebooks.
Bluetooth® was designed to provide low-cost, short-range
radio links between cellphones, notebooks and other portable
devices. The standard and its administration is governed by
the Bluetooth® Special Interest Group (SIG) which has more
than 5,000 members.
VConnectTM is a proprietary standard developed by
PSB Technologies for the dedicated purpose of establishing a
high quality wireless audio link. It sub-divides the ISM
frequency band into 38 virtual channels and continuously
scans to find channels with the lowest data packet losses.
When an operating channel results in unacceptable packet
loss, that channel is removed from the list of frequency
channels used by the frequency scanning algorithm.
VConnectTM also provides for error correction and
recovery through the re-transmission of data between
transmitter and receiver. This maintains the integrity of
the data stream and results in robust, interference-free
operations. No compression (or degradation) of the audio
signal is involved in the transmission scheme.
Feature Comparison Table
| |
Bluetooth® |
VConnectTM |
|
Operating
Frequency |
ISM Band |
ISM Band |
|
Bandwidth
(typical) |
1 Mbps |
4 Mbps |
|
Audio Quality |
Mono/FM
Stereo |
CD Stereo |
|
Uncompressed
Audio |
No |
Yes |
|
Instant ON |
No |
Yes |
|
Operating
Range (typical) |
5m |
20m |
|
Latency
(typical) |
170ms |
20ms |
Technical Notes
1. Bandwidth
VConnectTM offers a bigger pipe to pump more data
between the transmitter and receiver. In practical terms
this results in higher quality audio representation. In
Bluetooth® there is a need to compress the audio signals in
order to fit the narrow data pipe. Whenever there is
compression there is loss of data and hence quality
degradation.
2. Instant “ON”
Bluetooth® requires the transmitter and receiver to be
paired (matched). Even after the mandatory matching process
(once only), the transmitter needs to search for the
receiver after every device power ON.
3. Latency
Latency or delay is important when your application include
audio and video synchronization. This is typical of a home
theatre or surround sound system where you want the video
you are watching to be synchronized to the audio. The human
ear is able to detect any audio delay greater than 100ms. As
such Bluetooth® would not be suitable for such applications
as TV or movie audio. There is a greater delay in Bluetooth®
because of the complexity of its protocol (communications)
stack.
Prepared by: Product Design & Engineering Centre, PSB
Technologies.
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