AVL, Trackers
HDTV Antenna
& Tuner Box
Bluetooth Modules
EPROM, MCU
GPS, Receivers
GPRS/GSM/LTE Modules
LCD
RF Modules
Robotics
Voice Modules
Accessories

Credit Card Payment

Follow us on Twitter Facebook


What is sampling rate?

Sampling is the process of measuring an audio signal at specific points in time. Sampling rate (sr) is a term used in digital audio to describe the rate or frequency at whcih a signal is peridoically samples or measured. The sampling rate or frequency is expressed in Hertz. The sampling frequency in a compact disc player is 44,100 Hertz, which means that the audio signal is sampled 44,100 times per second. The higher the sampling rate, the better the representation of the original analog wave and better the sound quality. See table below.

Important Note

It is important to prepare the original sound file before re-sampling. For example, if the original sound has background noise, after re-sampling and programmed to the IC, those noises will be increased. Keep in mind that the playback quality can never be 100% as good as the original file because the playback method is not the same. For example, the original sound was played back on the PC with high quality speaker, sound card, etc; while the IC is played back from a circuit directly.

How to calculate

To calculate the maximum duration of each IC, it depends on the memory of the IC. Each of the OTP IC has memory size as below:

Duration10"21"42"85"170"341"
Memory0.25M0.5M1M2M4M8M

The general formula that gives the relation ship between the duration and sampling rate is:

 
 Duration (in seconds) = 
Memory Size of ROM (in Kb) / (Sampling rate (in KHz) x compression bits)

Note: The compression bits are ADPCM = 4 bits, PCM = 8 bits, 5-uLaw = 5 bits

Example I

For an 8M memory IC with 4 bit compression at 6 KHz sampling rate, the duration is:

    ( 1024 x 8 ) / ( 4 bit x 6 KHZ ) = 341 secs

Based on the sampling rate, the quality of the IC can be improved. If your application requires better quality, save the sound file at a higher sampling rate like 8 KHz or 12 KHz.

Example II

For the same 8M memory IC, if we use 8 bit compression and 12 KHz sampling rate, the duration is reduced from 341 secs to 85 secs.

    8192 / (8 bit x 12 kHz) = 85 sec

Sampling Frequency Rate Table (ADPCM / PCM)


 Memory Sampling Frequency Rate Duration
 6 Khz8 Khz 10 Khz12 Khz
AP89010
K161004
aIVR3K10
ADPCM64K 10 sec 8 sec6 sec5 secD = 64K / SR
PCM32K5 sec4 sec3 sec 2.5 secD = 32K / SR
AP89021
K162104
aIVR3K21
ADPCM 128K 21 sec16 sec12 sec10 sec D = 128K / SR
PCM32K10 sec 8 sec6 sec5 secD = 32K / SR
AP89042
K164208
aIVR3K42
ADPCM 256K 42 sec32 sec25 sec21 secD = 256K / SR
PCM128K21 sec16 sec12 sec 10 secD = 128K / SR
AP89085
K208511
ADPCM 512K85 sec64 sec51 sec42 sec D = 512K / SR
PCM256K42 sec 32 sec25 sec21 secD = 256K / SR
AP89170ADPCM1024K170 sec 128 sec102 sec85 secD = 1024K / SR
PCM512K85 sec64 sec51 sec 42 secD = 512K / SR
AP89341
K2N341N
ADPCM2048K 341 sec256 sec204 sec170 secD = 2048K / SR
PCM1024K170 sec 128 sec102 sec85 secD = 1024K / SR


Sampling Frequency Rate Table (5-uLaw)


 Memory Sampling Frequency Rate Duration
 6 Khz8 Khz 10 Khz12 Khz
K161004
aIVR3K10
51.2K 8 sec6 sec5 sec4 secD = 51.2K / SR
K162104
aIVR3K21
102.4K17 sec12 sec10 sec 8 secD = 102.4K / SR
K164208
aIVR3K42
204.8K 34 sec25 sec20 sec17 secD = 204.8K / SR
K208511 409.6K68 sec51 sec40 sec34 sec D = 409.6K / SR
K2N341N1638.4K 273 sec204 sec163 sec136 secD = 1638.4K / SR


Resistor (ohm) / Rosc values for Sampling Rate


Sampling Rate6 Khz8 Khz 10 Khz11 Khz12 Khz
aP89010,
aP89021,
aP89042
270K 200K150K140K120K
aP89085,
aP89170,
aP89341
270K 190K150K140K120K
aP8910A,
aP8921A,
aP8942A
344K 252K202K183K168K
KIVRxxxx610K

See also PCM vs ADPCM


More Products
  • K-IVR Voice
  • OTP - AP89xxx
  • OTP - AP89xxxK
  • OTP - AP23xxx
  • MultiTime Voice
  • 3Kx series
  • Sound Generator
  • Recordable Voice
  • Accessories
  • Sound Modules


  • Related Products
    PIR Sound Module
    Motion Activated
    Sound Module


    QCard
    Recordable Card


    Speakers
    Accessories


    Tech Notes
  • FAQ
  • PCM vs ADPCM
  • Sampling rate
  • Triggers Mechanism
  • Triggers Options
  • Rec vs OTP vs MTP
  • APR2060 ROSC value
  • OTP Comparison

  • FAQ | Terms & Conditions | Contact Us

    Copyright © 2017 Kowatec Corporation. All rights reserved.