Speech Synthesis LSI Selection Guide

ROHM SpeechSynthesisLsi

Speech Synthesis LSI Selection Guide
Basic knowledge of audio data
Listening to compressed audio data

Speech Synthesis LSI Selection Guide (Voice Memory Size Calculator)

Calculate the required voice memory size for your system!

We calculate the voice memory size of your product and propose the best LAPIS Technology Speech Synthesis LSI.

1. Enter the basic settings of the Speech Synthesis LSI

Grade: :
CPU I/F :
Play time :
* The playback time is a guideline at a sampling frequency of 8.0kHz with 4bit ADPCM2.
Memory type :

2. Input memory specifications and calculate memory size.

Synthesis method	Number of phrases	Average length of sound	Approximate memory size
	pcs	sec.	0 Mbit
	pcs	sec.	0 Mbit
	pcs	sec.	0 Mbit
	pcs	sec.	0 Mbit
The total memory size for storing audio data is 0 Mbit

3. We propose the following LAPIS Technology Speech Synthesis LSI that is most suitable for your system.

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	Data sheets	Supply Voltage (V)	Frequency Band (MHz)	Oscillator	Operating Temperature (°C)	ROM capacity (bit)	Playback phrase count	Maximum playback time(s)	CPU I/F	SP amplifier output (W)/class	Mixing number (interna) (ch)	Other	PKG	For automotive^*1	Sample and Buy

*1 : is for automotive use. can provide AEC-Q100 qualified products.

Type of synthesis method

Sampling frequency \ synthesis method		Description	Sound quality			Compression ratio	Play time (sec) * When the audio data size is 1Mbit
Bit rate	Method	Description	Human voice	Musics	Sound effect	Compression ratio	Fs = 8kHz	Fs = 16kHz	Fs = 32kHz
(Variable bit length) HQ-ADPCM ^*1		LAPIS Technology's unique method. This method enables high compression while maintaining high sound quality by changing the bit rate to a variable bit length. This is the higher-order method of the following 4-bit ADPCM2. It is suitable for various sound qualities such as human voice, animal voice, nature sound, music and sound effects. We recommend this method for new development or when you want to change from another method to one with higher sound quality and higher compression.	High-quality sound	High-quality sound	High-quality sound	1/5	40	20	10
4bit ADPCM2		LAPIS Technology's unique method. The audio data is digitized at regular intervals, high compression is achieved by taking the difference from the previous data, and the sound quality is improved by improving the followability of the waveform. Suitable for expressing human voices, animal voices, and natural sounds. If you are currently using this method and want to change to a higher sound quality and higher compression method, we recommend the HQ-ADPCM method.	High-quality sound	Low sound quality	Low sound quality	1/4	32	16	8
8bit non-linearPCM		LAPIS Technology's unique method. By recording 10bits near the center of the waveform, high compression and high sound quality are realized. Suitable for expressing low volume sounds or human voice. If you are currently using this method and want to change to a higher sound quality, higher compression method, we recommend the HQ-ADPCM method.	High-quality sound	Medium sound quality	Medium sound quality	1/2	16	8	4
8bit PCM		This is a general method. It is suitable for expressions such as music and sound effects, and for sound effects and pulse-shaped waveforms with sharp changes in waveform.	High-quality sound	High-quality sound	High-quality sound	1/2	16	8	4
16bit PCM		This is a general method. It is suitable for expressions such as music and sound effects, and for sound effects and pulse-shaped waveforms with sharp changes in waveform.	High-quality sound	High-quality sound	High-quality sound	1/1	8	4	2

*1 : HQ-ADPCM is Ky's high-quality sound compression technology. Ky's is a registered trademark of Kyushu Institute of Technology.

Phrase description

phrase	Description
Sampling Frequency (Fs)	When converting an analog signal such as voice to a digital signal, this is a numerical value that indicates how many times (quantization) should be performed for 1 second of data. The unit is Hz. For example, sampling is performed 8,000 times per second at 8kHz, and 16,000 times per second at 16kHz. The higher the sampling frequency, the better the sound quality. (Sampling frequency of 44.1kHz for music CD and 48kHz for digital broadcasting.)
Bit rate	It is a numerical value when the amount of data uttered per second is expressed in bits. For data of the same format and sampling frequency, the higher the bit rate, the better the sound quality. However, the amount of data is large.
Number of phrases	The number of types of sound to play. For speech synthesis LSIs, this is the number of addresses that can be set. For example, when playing "This is LAPIS Technology", one phrase is used for "This is LAPIS Technology", and two phrases for "This is" and "LAPIS Technology".

Sound effect

Synthesis method	HQ-ADPCM	4bit ADPCM2	8bit non-linear PCM	8bit PCM	16bit PCM
32kHz	PLAY	PLAY	PLAY	PLAY	PLAY
16kHz	PLAY	PLAY	PLAY	PLAY	PLAY
8kHz	PLAY	PLAY	PLAY	PLAY	PLAY

Melody

Synthesis method	HQ-ADPCM	4bit ADPCM2	8bit non-linear PCM	8bit PCM	16bit PCM
32kHz	PLAY	PLAY	PLAY	PLAY	PLAY
16kHz	PLAY	PLAY	PLAY	PLAY	PLAY
8kHz	PLAY	PLAY	PLAY	PLAY	PLAY

Guidance

Synthesis method	HQ-ADPCM	4bit ADPCM2	8bit non-linear PCM	8bit PCM	16bit PCM
16kHz	PLAY	PLAY	PLAY	PLAY	PLAY
12kHz	PLAY	PLAY	PLAY	PLAY	PLAY
8kHz	PLAY	PLAY	PLAY	PLAY	PLAY

* All copyrights of the sample audition sound source belong to our company and are protected by the Copyright Act. Unauthorized use of our sample listening sound source is prohibited by law.

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