Hello
On 11/28/2011 05:41 PM, Jens Erdmann wrote:
just a few quetstions:
1. Why is the device named EM2884_BOARD_CINERGY_HTC_STICK and not
EM2884_BOARD_TERRATEC_HTC_STICK like all the other devices from that
vendor? Looks inconsistent to me.
Developer have just chosen some value. Maybe he have not looked so
carefully about naming. Feel free to fix :) I think correct name is
something chip version + "board" + vendor name + device name and model.
If name goes something like very long it could be shortened.
2. I stumbled over http://linux.terratec.de/tv_en.html where they list a NXP TDA18271
as used tuner for H5 and HTC Stick devices. I dont have any experience in this
kind of stuff but i am just asking.
DVB device contain logically three chips. Those are;
1. interface chip (USB, PCI)
2. demodulator
3. tuner
Those parts can be integrated even as one silicon (called 3-in-1). Very
commonly it seen combination 1.+2. in one chip and 3. in other == total
2 chips.
EM2884 is interface chip. It is called usually DVB USB bridge since it
transfers bits from demod to computer.
TDA18271 is tuner. On the other side of chip is antenna connected as
signal input and output is IF (intermediate frequency). Tuner can be
thought as chip that transfers signal from RF (radio frequency) to IF
(intermediate frequency). Demodulator then takes that IF from tuner and
encodes bits out from signal. Interface between demodulator and bridge
is bit interface and it is called MPEG2 TS (transport stream) interface.
There is also second interface for controlling each chip. That interface
is usually I2C bus. Each chip (demod and tuner) is connected to the
I2C-bus-adapter which is part of bridge. All command to chips are send
using that I2C interface.
regards
Antti
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http://palosaari.fi/
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