Recall1 DVB-T diy

DVB-T platform build in Cheertek main chip with transcoder and could receive DVB-T tuner signal then transfer into Video,Audio signal same time.
DVB-T got remote control ability through UR interface.


Platform rear view.



RF tuner zoom in picture.
DVB-T tuner use Quantel receiver and Afa9003 transcoder.

Diy8 DAB receivre

DAB tuner Hitachi receiver & SAW build in  support VHF Band-III & L-Band (1.5GHz)

Baseband Ti32C5416 DSP with bus bridge connect USB controller.
Could play DAB audio and send DLS（Dynamic Label Segments）through USB same time.

DAB tuner mount on baseband platform.
DAB box inner connection with power module and audio connector.
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ToyX project EQ Linearizer study case1

I design a DIY EQ Linearizer call X project.
Simulate the band filter for to correct phase shift issue.
The 5 band pass CF will be 50Hz,250Hz,1KHz,4KHz,12.8KHz.

50Hz first band in band1
Band1: 5~100Hz(5 pcs 20hz band pass filter inside 5~20,20~40,,80~100hz)
橫跨頻寬20Hz 中央是相位0度,左-Pi 是-180度 & 右+Pi是 +180度相位 .

Use other program to verify L-C frequency.

250Hz first band in band2
band2:250Hz (5 pcs 60hz band pass filter inside 100~160,160~220,,340~400hz)
橫跨頻寬60Hz 中央是相位0度,左-Pi 是-180度 & 右+Pi是 +180度相位 .

1KHz first band in band3
band3:1KHz (5 pcs 240hz band pass filter inside 400~640,640~880,,1360~1600Hz..)
橫跨頻寬240Hz 中央是相位0度,左-Pi 是-180度 & 右+Pi是 +180度相位 .

4KHz first band in band4
band4:4KHz (5 pcs 1Khz band pass filter inside  1.6K~2.56K,2.56k~3.56k,,5.4K~6.4KHz)
橫跨頻寬1KHz 中央是相位0度,左-Pi 是-180度 & 右+Pi是 +180度相位 .

12.8KHz first band in  band5
band:12.8KHz(5 pcs 2.56K band pass filter inside 6.4K~ 9.86K,9.86k~11.52K,,16.64k~19.2Kband...)
橫跨頻寬2.56KHz 中央是相位0度,左-Pi 是-180度 & 右+Pi是 +180度相位 .

由此可知........
低頻橫跨頻寬20Hz 中央是相位0度,左右差10Hz 分頻器相差就達到180度相位 誤差.
低頻分頻器相差 ,造成訊號失真大,破壞音質,而不只是分頻器相差, 造成時間差而已 .
低頻分頻器相差 ,造成訊號失真, 聲音就易糊成一團 ,低頻彈跳感減弱.

.........................不知數位及DSP 等化器要如何補, 如何調?

Toy10 Audio media center

For More francy sound color and sound detail I DIY PCI media play card.

Diy Audio PCI card with two type.
Left type use VIA VT1720T PCI Media player control + codec WM8740 + OP and buffer (could 24bits/192K @kernel streaming ).
Just depend PC performance.

Right type just use VIA VT1720T Media player control and direct SPDIF output fiber signal only.


PCI Audio control VIA1720T,Codec WM8740.
These card need firmware code and special driver on windows XP system.
Because I prefer kernel streaming direct play wav. format music and no XP mixer to distortion and change sample rate.
I setup working sample rate is 24bits/96K(kernel streaming mode).


Audio media center front view with hand make PCB case.


7'' LCD,CD-ROM,Optical Spdif out,Wifi build in.


LCD dislay.


Audio media center bottom view.

Hand make cooling fans and switching power.