Showing posts with label signal. Show all posts
Showing posts with label signal. Show all posts
Friday, September 26, 2014
Build a Relay Switch Activated by Tone and Signal
The essence of the circuit is for the input of tone and signal to provide an activation for the relay switch.
- Relay – an electrically operated switch where the current flowing through the coil of the relay is creating a magnetic field which attracts a lever and changes the switch contacts, thereby making its state open or close
- BC214 – a complementary silicon planar epitaxial transistor used in AF small signal drivers and am1 as well as for low noise preamplifier applications due to its feature of good linearity of DC current gain
- LM741 – a general purpose single operational amplifier with features such as offset null, compensated internal freq uency, voltage range with high input, good stability of temperature, and protected from short circuit
The use of relay will allow the circuit to switch from one condition to another. It can also be referred to as a form of an electrical amplifier since it is able to control an output circuit of higher power than the input circuit. There are many types of relays being used in many electronic and electrical circuits, which include solid-state relay, Buchholz relay, overload protection relay, latching relay, forced-guided contacts relay, mercury-wetted relay, contactor relay, machine tool relay, reed relay, polarized relay, and solid state contactor relay.
The circuit created is sensitive enough to the AC signals in the input stage, where the signals are ranging above 5 mV. It will also be sensitive to react with the human voice signals having a range of frequency from 50 Hz up to 3 KHz. The human voice is a part of the human sound produced primarily by the vocal cords or vocal folds which in turn produces a voice frequency that is used for the transmission of speech.
During the absence of an input signal, the state of the 12 V relay RL1 is at OFF condition as regulated by the 10K Ohms trimmer RV1. The circuit can be made to react with its sensitivity in points A, B, & C, where a negative feedback can be placed due to the addition of band pass filter. The filter will operate only in the 1 KHz range and the circuit will only correspond at this frequency.
During the absence of an input signal, the state of the 12 V relay RL1 is at OFF condition as regulated by the 10K Ohms trimmer RV1. The circuit can be made to react with its sensitivity in points A, B, & C, where a negative feedback can be placed due to the addition of band pass filter. The filter will operate only in the 1 KHz range and the circuit will only correspond at this frequency.
The signal and tone activated relay switch were used in a wide range of fields which includes measuring instruments, audio systems, communications equipment, and factory-automation equipment. They can also be found on telephone subscriber circuits for the polarity reversing switch, testing, and ringing functions. Source
Tuesday, January 28, 2014
Process formation of RGB signal on TV
Basically the UOC is equipped with RGB or YUV input from external, so it is possible to use the DVD input. Selection of these inputs can be done internally within the IC. But in the G7 and G7A chassis input YUV signal is not used, so in the ground.
RGB signal processing flow is described according to the image below :
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| Diagram of the formation RGB signal |
1. Signal Yint, uint, and Vint is derived from a series of color decoder and Y / C switch is fed into a series of YUV selector 1.
2. From YUV selector, sub-carrier signal color (U and V) is inserted into the chain matrix. In this matrix series component sub-carrier signal BY of the color (U signal) and BY component of sub-carrier signal color (V signal) in separate. Here the color difference signal in the form of the color sub carrier. GY signal generated by a combination of color difference signals RY and BY.
3. From YUV selector, luminan signal is passed to a series of black stretch. The working principle is to sharpen the series of black stretch black levels. Gray color in a certain percentage in drag to a black color so the color is sharper.
4. Three color difference signals (RY), (BY) (GY) and luminan signal (Y) are mixed and processed in RGB adder circuit to produce three primary colors red, green and blue (RGB).
5. RGBOSD formed in the UOC IC is used to display the OSD text. The selection and arrangement RGBOSD kontrast between RGB and composite signals is done by way of a switch by the internal microprocessor.
6. Three output video signal (RGB signal) is assumed as the current that flows to the CRT cathode. Drive level coming into the cathode tube is always diadjust by CCC loop (Continues Cathode Calibration) and feedback currents in pass to Black Current Input pin 50.
7. CCC loop works as a stabilizer against the black level and drive the cathode in a loop (continuous) to the RGB signal in order to obtain the proper offset and gain.
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| CCC Loop Application |
Saturday, December 7, 2013
Sound Signal Processor with MSP 34X0G
IC MSP 34X0G is a single chip that can process voice signals to all TV standard International, and very good for the digital NICAM stereo. In the IC has several advantages, namely:
- Communication using the I2C bus control
- Selection of a voice signal automatically (mono / stereo / bilingual)
- Loudspeaker / headphones are equipped with volume control, bass, treble, loudness and balance
- Loudspeaker outputs are equipped with MDB (Micronas Dynamic Bass)
- AVC: Automatic Volume Correction
- Equipped with Sub woofer output
- Have facilities 5-Band graphic equalizer for loudspeaker
- Equipped spatial effect for loudspeaker
- Equipped with a matrix of voters in / out
- Has a SCART 4 stereo inputs, one mono input and 2 stereo SCART output
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| Block diagram of circuit in the IC MSP34X0G |
Thursday, November 28, 2013
Signal Tracer using LM386 Amplifier Chip
The main part of this circuit is the LM386 amplifier chip. It also uses a transistor input to buffer the input signal and provide extra gain for the LM386. The little unit has helped me out on numerous occasions when trouble shooting any amplifier circuit like a stereo receiver, tv / vcr audio section, radios, cd players and car stereos.
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