White Paper T630/T628
Polyphonic ring signals
Protocol
The T630/T628 has a hardware synthesizer chip, built into the mobile phone. The software controls the MIDI files, and makes sure they fit into the hard- ware chip. It is possible to modify the dynamics, and it is possible to make the sound escalate, start quietly and grow louder.
The T630/T628 Sony Ericsson mobile phone com- pletely supports the MIDI 1.0 detailed specification. Please visit http://www.midi.org/ for more informa- tion.
The quality of the sound heard from the speakers depends on many different things, for example on the synthesizer, the amplifier, or the speakers. An important factor for sound quality is the number of voices. The human ear cannot separate each voice if the number of voices increases above about 16, then the voices merge together. But the nuances in the music increase, and the music is experienced as more sophisticated if the number of voices increases. Many modern sound modules in synthe- sizers used by musicians have 16, 24 or 32 note polyphony. The number of voices used in the T630/ T628 is 32, which gives excellent sound quality.
Excellent sound quality – 32voices
The human ear can hear sounds from approxi- mately 20 Hz up to 20 KHz. In most GSM mobile phones, the speech sound range is from 300 Hz to 3400 Hz, which is good enough for speaking, but quite poor for music. The T630/T628 can handle up to 15000 Hz, equivalent to an FM stereo radio, which means excellent sound quality.
T630/T628 has a dedicated speaker to ensure the best possible sound quality. This speaker is situ- ated on the back of the phone ensuring no discom- fort is felt if a second call is received during an ongoing call. It also ensures louder ring signals and removes the need for escalating rings signals.
Wavetable synthesis
Sony Ericsson has chosen to implement the Wavetable synthesis, which consists of sampled real instruments, which gives a much higher quality than the
Touch correct feature
The so called “Touch correct” feature makes dynamic compression possible. This equalizes the amplitude of the instruments included in the MIDI file, which greatly improves the sound quality, especially in melodies with big differences in ampli- tude.
Bluetooth™ wireless technology
The T630/T628 features
Bluetooth wireless technology is designed to be fully functional even in noisy radio frequency envi- ronments. All data transfer is protected by advanced
vided under adverse conditions, making it possible to use a headset connection to the T630/T628 at all times.
Ericsson was a founding partner of the Bluetooth Special Interest Group (SIG). Bluetooth wireless technology devices that are expected to be availa- ble in the near future, include:
•Headsets for wireless voice transmission and remote call control
•PCs, laptops, PDAs, palmpads for data transfer, synchronization etc.
23 | October 2003 |
