Principles of Sigma Delta Conversion for ADC

Principles of Sigma Delta Conversion for Analog to Digital Converters

Publish at Scribd or explore others: Academic Work Science & Engineerin software media

Digital System and Application: The Computer Engineering Handbok (ebook)

Digital System and Application the Computer Engineering Handbook Second Edition

Publish at Scribd or explore others: Science & Engineerin eBooks digital system and a computer engineering

New Wireless Standard Promises Ultra-Fast Media Applications

New Wireless Standard Promises Ultra-Fast Media Applications
Georgia Institute of Technology (01/22/09) Fernandez, Don

The Georgia Institute of Technology's Georgia Electronic Design Center (GEDC) has developed a complementary metal oxide semiconductor (CMOS) chip capable of transmitting 60 GHz digital radio-frequency signals. GEDC researchers say the technology could lead to the rapid transfer of high-definition movies and other large files from a PC to a cell phone, virtually wireless desktop computers and data centers, wireless home DVD systems, in-store kiosks that can download movies to mobile devices, and the ability to move gigabytes of photos or video files from a camera to a PC almost instantly. "We believe this new standard represents a major step forward," says GEDC director Joy Laskar. "Consumers could see products capable of ultra-fast short-range data transfer within two or three years." GEDC's chip provides multi-gigabit wireless transmissions by combining 60 GHz CMOS digital radio capabilities and multi-gigabit signal processing in an ultra-compact device. Laskar says the new technology represents the highest level of integration for 60 GHz wireless single-chip solutions. "Multi-gigabit technology definitely has major promise for new consumer and IT applications," says Microsoft Research's Darko Kirovski. GEDC researchers say they have already achieved high data transfer speeds that could lead to unprecedented short-range wireless speeds, including 15 Gbps at 1 meter, 10 Gbps at 2 meters, and 5 Gbps at 5 meters.

User Timer in Linux/Unix

#include <sys/time.h >  
#include <signal.h >
#include <stdlib.h >
#include <stdio.h >

#define MAX_COUNT   100

/* This flag controls termination of the main loop. */
volatile sig_atomic_t counter = 0;

/* The signal handler just clears the flag and re-enables itself. */
void
catch_alarm (int sig)
{
    counter++;
    signal (sig, catch_alarm);
    //    printf("\nCatch an alarm!\n");
}


void do_stuff (void)
{
    static unsigned long c = 0;
    printf ("Doing stuff while waiting for alarm (myCounter = %u,    Counter=%u)          \r", ++c, counter);
}

void set_timer_val(struct itimerval *t, const unsigned long ival_usec, const unsigned int val_usec)
{
    //period between successive timer interrupts
    t->it_interval.tv_usec = ival_usec % 1000000;
    t->it_interval.tv_sec = ival_usec / 1000000;
    //period between now and the first timer interrupt
    t->it_value.tv_usec = val_usec % 1000000;
    t->it_value.tv_sec = val_usec / 1000000;
}

int main (void)
{
    struct itimerval ival, oval;

    /* Establish a handler for SIGALRM signals. */
    signal (SIGALRM, catch_alarm);

    /* Set an alarm to go off in a little while. */
    // one-shot timer
    set_timer_val(&ival, 1000000, 500000);
    setitimer (ITIMER_REAL, &ival, &oval);

    /* Check the flag once in a while to see when to quit. */
    while (counter < MAX_COUNT)
        do_stuff ();

    printf("\n");
    return EXIT_SUCCESS;
}

Creative XtremeGamer on Linux is Ready

The XFi driver is now available from Creative website. It's the first version (I think it is the first collaboration result between CreativeLabs and ALSA community). Although it supports very limited (very basic features: 2.0 speakers, no enhanced audio processing etc.) right now. At least, my OpenSUSE can spit out sound!

Get it from here.
extract it, but don't make it yet. Modify ctdrv.h. In my case, it shows like below:

#ifndef CTDRV_H
#define CTDRV_H

#define PCI_VENDOR_CREATIVE                     0x1102
#define PCI_DEVICE_CREATIVE_20K1        0x0005
#define PCI_DEVICE_CREATIVE_20K2        0x000B
#define PCI_SUBVENDOR_CREATIVE          0x1102
#define PCI_SUBSYS_CREATIVE_SB0760      0x0024
//#define PCI_SUBSYS_CREATIVE_SB0880    0x0041
#define PCI_SUBSYS_CREATIVE_SB0880      0x6003

#define PCI_SUBSYS_CREATIVE_HENDRIX     0x6000
//#define PCI_SUBSYS_CREATIVE_HENDRIX   0x6003

#define CT_XFI_DMA_MASK                 0xffffffffUL /* 32 bits */

That is because when I do:

Make a sound card as default in Linux

In the case that we have more than one sound-card, but to select one of them as the default sound-card, copy the following to ~/.asoundrc. In the example below, it makes the card 1 as the default (type "aplay -l" from shell to see all the cards installed and their associated card #).

pcm.!default {
type hw
card 1
}
ctl.!default {
type hw
card 1
}