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173 Threads found on edaboard.com: Why Modulation
How to draw the Phasor diagrams of A.M and F.M. what are the reasons for the following two cases (1). In A.M the resultant of the two side band vectors is always in-phase with carrier component ,why? (2). In F.M the resultant side band vector is always in phase-quadrature with carrier component,why?
why did you double the frequency shift specification? +/- 30 kHz sounds more like a reasonable range for 433 MHz band. Anyway, if the DEV input isn't suited to achieve the intended shift, you need to modify the transmitter circuit.
Always my problem - a manager's review of me once included "why use 1 word when 20 will do"!!! Susan
i need two levels of voltage to be fed to the motor. i.e, 90V and 230V. why, particularly? Usually motor voltage is varied continuously by means of pulse width modulation. why cant we directly give the boost converter output to inverter. You can, if no isolation is required and the voltage level is appropriate fo
why and how does channel length modulation occurring in mosfets decrease the gain of amplifiers?
This code is simply a registered multiplexer of two constants, why is this so hard to figure out or determine if it works (by inspection alone)?
library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL; -- Entity Declaration entity bpsk_mod is Port ( clk : in std_logic; -- Processing clock valid_in : in std_logic; -- Input valid signal data_in : in std_logic; -- Input data signal reset : in std_logic; -- Asynchronous reset sig
I too think it is 'poorly' named as you can't connect more than one physical device to the same port. You can however have several 'end points' on one physical device so perhaps that is why they call it a bus. Brian.
LPF out is average of "mod" voltage, not peak. Review the waveform and you'll understand why the output can't be 1 V.
There is a very simple reason for that, changing L changes the device properties significantly while you can increase the W by just putting multiple of these devices together. Also you would probably want to use a shorter channel usually because if you're going for a longer channel length why not just use an older, cheaper process. That is not to
why do you want to make an inverter but you cannot find a transformer for it?
Although it is SSB modulator with LSB output, changing sign in DSP formula will modulate output to upper side band. why are you preceeding well-known signal processing facts with the word "although"? It's exactly as you assume.
Dear All Not being an analogue design engineer, can anybody tell me why the attached circuit could not be used to modulate a 20mA LED laser diode at 1GHz? I do not need 100% modulation. The spice simulation shows the modulated current as 13 - 20mA with +/- 3mA p-p supplied by the oscillator. Spice simulation attached. 113484[/ATTACH
NEVER connect LEDs in parallel unless you match their forward voltage. Pulsed LEDs appear to be dimmed which is why Pulse-Width modulation is used to dim car and bus tail lights. Your eyesight needs an on-time of 30ms or longer to have the same brightness as continuous current. If you pulse with over-current at a low frequency then the long on-
Instead of playing with I and Q signal after demodulation, why don't you think to make an AGC circuit at RF side of this receiver ?? For instance using a RF RSSI IC ( for instance from Analog Device ) will simplify your AGC circuit because these circuits work independent from modulation. I hope I understood your target well a simple cahin (...)
1553 modulation is Biphase , so clock recovery to 0.1% long term is normal, short term depends on Noise and method used, PLL or 1-shot at 3/4T i have no idea why they specify freq error on Biphase , when for Rx, only phase noise and phase margin counts.
why Data transmission at higher rates requires wider bandwidths?
Apart from the technical difficulties of dealing with controlled super high frequencies, and the danger of seeing inside my head (it's a dark, dark place!) you should consider why we use X-ray and gamma rays in existing applications. X-rays are used because they are easily blocked by dense objects, thats how they produce photographs to show our in
1. How do we choose a particular modulation scheme in RF Transceiver (Zigbee uses OQPSK),(Bluetooth LE uses GFSK).why zigbee uses OQPSK and BLE uses GFSK?why not other modulation schemes? 2. Is there any relationship between modulation scheme and path loss?.
Sensitivity is also function of wanted signal-to-noise ratio.You can also say for that as EVM,BER etc. That's why calculation only doesn't make sense mostly depends on the modulation,bit rate which you intend to use. You calculated signal level at the RX antenna and it has little meaning in terms of sensitivity.