Showing posts with label tv. Show all posts
Showing posts with label tv. Show all posts

Tuesday, November 18, 2014

Different types of TV TUNER

TV tuner that is used on older models and new models of television there are some differences. Therefore, understanding the different types of tuner would be useful if we want to replace the tuner with the other models.
Supply voltage tuner.
Tuner older models generally use a supply voltage of 12v, the new models are commonly used 5V supply voltage. Some use a 9V voltage, but very rare.

TV TUNER
Voltage Synthesizer tuner (VS tuner)
Tuner that uses a tuning control (VT or BT) with a voltage between 0 to 33V Voltage Synthesizer tuner named. TV can be found on the aircraft models, old and new
Based on how the control band-switch, Tuner VS then there are 2 kinds, namely
Using 3-Band input sw, the VL-VH-U
Using 2-Band input sw, the Band SW1 and SW2 Band. This tuner is actually similar to the type of band 3-sw. For control-sw 2 band is in the tuner will still be converted into 3-sw bands.

Frequency Synthesizer tuner (FS tuner) or the type of PLL
Tuner wherein the tuning voltage and the voltage controlled band switching the digital communication through SDA and SCL. This tuner has a supply voltage Vcc, which is
5V is used for the digital tuner circuit control and
33V (fixed voltage or fixed) is used to control the voltage supplied to the tuning in the digital circuits within the tuner.
(Tuner old) sometimes there are additional circuit voltage of 12V to the tuner.

Frequency band.
Based on the wide range of revenue-frequency band, there are three kinds of tuner
Normal tuner
Superband tuner
Tuner hyperband

Normal tuner, the tuner that can receive broadcasts "on-air" (terrestrial) TV in the frequency band:
  • Frequency of VHF Band I - VL 41-68 Mhz
  • Band III - VH 174-230 Mhz
  • Frequency UHF Band IV - U 470-581 Mhz
  • Band V - U 582-960 Mhz
  • Band II 87.5 - 104 MHz is used for FM radio broadcasting
  • VL and VH bands used for broadcast channels 2 through 12
  • U bands used for broadcast channels 21 to 69
Superband Tuner and Hyperband, the tuner can receive broadcast as normal tuner plus the ability to receive broadcasts "off air" CATV (cable television).
  • S band using frequency band between VL and VH
  • H-band using a frequency band between VH and U
  • Superband Tuner can receive the broadcast band S
  • Hyperband tuner can receive broadcast band and S band H
Based on the IF frequency out
IF frequency tuner out there who have 38/38.9/45.75 Mhz frequency. In Indonesia generally use 38.9Mhz frequency, but sometimes there is a use 38.0Mhz


Based on the pin-out
There are several kinds of tuner long pin-out configuration. But now almost all the tuner is already using an international standard 11-pin

Universal tuner
China is now producing "universal tuner" 11-pin. Indonesia was just the market we do not know whether it exists or not. This tuner can be used to substitute for the various types of tuners and tuner can adjust to this direct voltage of 5, 9, or 12v.

RF antenna input connector
Form the antenna input connector there are two kinds, namely:
  • RCA type connectors
  • Antenna RF connector
Tuner modules
Tuner is a tuner module inside there are all Video IF amplifier circuit and the FM-detector. This kind of tuner is using VS and some are using the FS.
Tuner module has output like:
  • RF AGC-out
  • RF AFC-out
  • Audio-out
  • Video-out
  • Base band out, the signal to be processed into stereo sound circuit.
Except that in tuner is also sometimes diperlengkapa with audio-switch to TV / AV-in. Therefore, to the sound of the AV-in connected via Audio-in found on the tuner module. Sometimes the sound volume to be controlled in the tuner module.
  • SONY tuner module 1
  • SONY tuner module 2
  • Toshiba tuner module
Impedance input / output
Impedance tuner has all kinds of input / output 75 ohm.

How to distinguish 2-band tuners VS sw with PLL tuner FS
In all these circumstances and the removable pin 11 feet was not cut, it is sometimes difficult to distinguish between two band-tuner tuner sw with FS.
Some models have a tuner pin legs partially emptied. FS Tuner has a location pin 30V voltage 3 numbers from the back (of the IF pin out).
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Saturday, September 13, 2014

TV Video Transmitter Wiring diagram Schematic

This schema is a video transmitter that has many uses, such as video cameras, security cameras, satellite receivers, DVD, Video Games, etc. .. The schema transmits 470-580MHz and can be tuned in the UHF channels 21-34. The video transmitter can reach up to 300 meters in open field using a wire antenna of 10-20 cm.
TV Video Transmitter Circuit Diagram

TV


Video Transmitter

Transmitter can work with a voltage from 9 to 15 volts. However, you can also use a 9v battery. Oscillator is based around BF199 and BFR90 is the RF transistors. If necessary, the transmission power can be increased by replacing with BFR90 transistor 2N3886.
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Friday, August 29, 2014

Main function of TV tuner

MainThe main function of the tuner is to select the RF signals from the desired frequency spectrum wave on VHF and UHF and more signs in the air Changing RF variable into a fixed IF frequency and to provide sufficient strengthening to cover the original data that has been transmitted.


Block diagram of a series of TV tuner to receive the frequency VHF / UHF

blok


Operational Tuner [Theoretical]

Tuner is controlled by a microprocessor in the TV chassis, which functions to receive / select a frequency. Exchange of information is channeled through the terminal Address, Clock and Data.

In the tuner, there are ICs that function to translate the instruction / data so that the tuner can function to select the desired frequency. The IC consists of some combination of series, including PLL, Local Oscillator [VCO], Mixer and IF amplifier. Everything artifacts in one chip / one chip. For further analysis, CXA3135 IC with I2C format will be taken as an example.
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