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DVD Signals RF modulator Circuit

A simple Remote tester to check all types of Remote hand sets……. This simple remote tester can be a good tool to check whether a remote hand set is working or not. It uses the commonly available IR sensor TSOP 1738.The IR sensor has a PIN photodiode and an FET signal amplifier enclosed in an Epoxy case. The sensor requires five volts for its operation and its output is active low. Normally its output gives + 5 volts and goes down to zero when it receives 38 KHz pulsed IR rays. When the remote handset is focused on to the sensor and any one button is pressed, buzzer beeps and LED blinks indicating that the handset is OK. Remote Tester Circuit Diagram

You can build a simple 1KHz square wave generator using a few components and the LM3909 that is useful for testing audio equipment. It is powered from a single 1.5V battery cell and the maximum amplitude of the output signal is 1.1V. With P1 you can adjust the symmetry of the square wave signal and with P2 the amplitude. Square wave generator schematic

This RF power amplifier is based on the transistor 2SC1970 and 2N4427. The output power is about 1.3W and the input driving power is 30-50mW. It will still get your RF signal quit far and I advice you to use a good 50 ohm resistor as dummy load. To tune this amplifier you can either use a power meter/wattmeter, SWR unit or you can do using a RF field meter. RF Amplifier Assembly Good grounding is very important in a RF system. I use bottom layer as Ground and I connect it with the top with wires to get a good grounding. Make sure you have some cooling at the transistor. In my case I put the 2SC1970 close to the PCB to handle the heat. With good tuning the transistor shouldn't become hot. RF Amplifier Printed Circuit Board You can download a pdf file which is the black PCB. The PCB is mirrored because the printed side side should be faced down the board during UV exposure. To the right you will find a pic showing the assembly of all components on the same board. This is how the real board should look when you are going to solder the components. It is a board made for surface mounted components, so the copper is on the top layer. I am sure you can still use hole mounted components as well. Grey area is copper and each component is draw in different colors all to make it easy to identify for you. The scale of the pdf is 1:1 and the picture at right is magnified with 4 times. Click on the pic to enlarge it. Low-Pass Filter Some of you might want to add a low-pass filter at the output. I have not added any extra low pass filter in my construction because I don't think it is needed. You can easy find several homepages about low pass filter and how to build them.

This HD TV UHF wideband amplifier(Ultra High Frequency amplifier) has a total gain of 10 to 15 dB in the 400 – 850 MHz domain frequency so it can be used where the tv signal is weak. For this UHF antenna tv amplifier to work correctly you need to cut the components pins as short as possible. C1, C2, C6, C7 are SMD type ( surface mounted ). This antenna tv amplifier or uhf wideband amplifier need to be build inside of a metal box and then connected close to the tv antenna. Prototype pictures (Prototip resimler) Antenna HD TV UHF band amplifier circuit schematic (Anten HD TV UHF bandındaki amplifikatör devre şeması) PCB layout for Wideband HD TV UHF Antenna TV Amplifier Circuit using transistor 2sc3358 (Baskı Devresi) The power supply is a simple 12V stabilized source. The antenna tv amplifier can be connected directly to the power supply thru coaxial cable of the tv antenna but you need a 10 – 100uH coil on the alimentation line. The tv set will be connected to the uhf amplifier thru a small coupling capacitor. Adjusting is easy, just bring the P1 to the middle and then adjust it untill you obtain the best tv image quality. Digital Tv antenna UHF amplifier components (Devrede kullanılan malzeme listesi): T1 -Transistor 2sc3358C1 – 10µF/35vC2,C9 – 1nFC3 ,C4 – 10nFC5,c6,c7,c8 – 10pFR1 – 470 OhmsR2 – 2.2 KR3 – 1KohmsP1 – 5KohmsL1,L2 – 2 turns 22AWG , 3mm Ø.L3,L4 – 10uH or 10 turns, 0.2mm Ø on ferrite..12 volts special power supply. 2sc3358 Transistörü kullanılarak Geniş Bant DTV UHF Anten TV Amplifikatör Devresi