Re: Need good quality Audio output through LPC21xx controller
- From: "Ulf Samuelsson" <ulf@xxxxxxxxxxxxx>
- Date: Tue, 30 Sep 2008 20:00:58 +0200
<angaddhot@xxxxxxxxx> skrev i meddelandet
news:0f148d36-bf58-48e7-9a34-1db113920ee2@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Sep 30, 6:56 pm, Vladimir Vassilevsky <antispam_bo...@xxxxxxxxxxx>
wrote:
angadd...@xxxxxxxxx wrote:
We are working on a project based on Vehicle tracking system.In one of
our module we are using audio(voice) for Public transport system.As
if for now we are using filters and a power amplifer We are not able
to get good quality audio output with this setup.
Item used:
Lpc2132 with MMC card interface ,High pass filter+ Low pass filter+
Audio Amplifier+ Speaker
Requirement:
Good Voice quality annoucement system for Public transport System
With PWM at 32kHz carrier and 8bit quantization, you can get a
"telephone line" quality speech. It would be even better if you apply
the preemphasis and the noise shaping to the recorded signal. You can
gain somewhat more quality if you combine several PWM channels. However
if you need the "music" quality audio, you should use an external DAC.
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultanthttp://www.abvolt.com
What about DAC codec ??
It needs I2S interface which is not available with LPC21XX.
If anyone know how to convert SSP from microcontroller controller to
I2S format in software.
==> There are plenty of controllers out there with I2S.
The AVR32 based UC3A3 has SD-Card I/F,
High speed USB, and I2S (as well as ADC/DAC)
Should be considerably faster than the LPC as well.
If you insist on ARM cores, then the AT91SAM7A3
has SD-Card interface and I2S interface (SSC).
--
Best Regards,
Ulf Samuelsson
This is intended to be my personal opinion which may,
or may not be shared by my employer Atmel Nordic AB
.
- References:
- Need good quality Audio output through LPC21xx controller
- From: angaddhot
- Re: Need good quality Audio output through LPC21xx controller
- From: Vladimir Vassilevsky
- Re: Need good quality Audio output through LPC21xx controller
- From: angaddhot
- Need good quality Audio output through LPC21xx controller
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