· There is a large dependence of fading on distance.
o The probability of a fade of a particular depth increases with the cube of
distance. Thus, as the distance is doubled, the probability of a particular fade
depth increases by a factor of eight. Or, alternatively, the fade for a given
probability increases by 9 dB. So, doubling the distance will increase the freespace
loss by 6 dB, and increase the probability of fading by 9 dB, thus
increasing the overall link-budget loss by 15 dB.
· There is a slight dependence of fading on frequency. Increasing the frequency by
1GHz will decrease the probability of a fade by a factor of 1.08.
· There is a fairly strong dependence of fading on the height of the path above sea
level.
o There is simply less atmosphere at higher altitudes and therefore the effect of
o For every 1000 meter increase in altitude the required fade margin reduces by
10 dB.
o Fast fading - occurs when the coherence time of the channel is small relative
to the delay constraint of the channel. Fast fading causes rapid fluctuations in
phase and amplitude of a signal if a transmitter or receiver is moving or there
are changes in the radio environment (e.g. car passing by). If a transmitter or
receiver is moving, the fluctuations occur within a few wave lengths. Because
o Slow fading - arises when the coherence time of the channel is large relative to
the delay constraint of the channel. Slow fading occurs due to the geometry of
the path profile. This leads to the situation in which the signal gradually gets
weaker or stronger.
o Flat fading – occurs when the coherence bandwidth of the channel is larger
than the bandwidth of the signal.
o Selective fading – occurs when the coherence bandwidth of the channel is
smaller than the bandwidth of the signal.
o Rayleigh fading - assume that the magnitude of a signal that has passed
through a communications channel will vary randomly.
o Ricean fading - occurs when one of the paths, typically a line of sight signal, is
much stronger than the others.
o Nakagami fading - occurs for multipath scattering with relatively larger timedelay
spreads, with different clusters of reflected waves.
o Weibull fading - considers a signal composed of clusters of one multipath
wave, each propagating in a non-homogeneous environment.

Build a Low Noise And Drift Composite Amp Circuit Diagram

How to Build a Low Noise And Drift Composite Amp Circuit Diagram. This circuit offers the best of both worlds. It can be combined with a low input offset voltage and drift without degrading the overall system`s dynamic performance.
Low Noise And Drift Composite Amp Circuit Diagram

Compared to a standalone FET input operational amplifier, the composite amplifier circuit exhibits a 20-fold improvement in voltage offset and drift. In this circuit arrangement, A1 is a highspeed FET input op amp with a closed-loop gain of 100 (the source impedance was arbitrarily chosen to be 100 kfl). A2 is a Super Beta bipolar input op amp. It has good dc characteristics, biFET-level input bias current, and low noise. A2 monitors the voltage at the input of A1 and injects current to Al`s null pins. This forces A1 to have the input properties of a bipolar amplifier while maintaining its bandwidth and low-input-bias-current noise.

High Power Output Amplifier TDA7294

The famous SGS-THOMSON ST Microelectronics has introduced a Hi-Fi DMOS high-power amplifier circuit TDA7294, its sound great taste bile, which due to its internal circuit from input to output are field-effect devices, rounded sound Mild, delicate Rounuan.  However, with its assembly amplifier, only TDA7294 single-output power is only 70 W, BTL access law is 100 W from top to bottom, do not feel that power cushion. The author several tests, used to promote TDA7294-level, direct-drive one to four pairs of high-power transistor parallel, the output of strong currents, the power output of 400 W (mono), and the circuit is simple and no need to debug that can reliably work Basically, the IC has maintained a sound and performance.  Ruzuo The figure below shows, R6 for the feedback resistor, the author of the value in debugging 22 k Ω more appropriate, R6 also decided this circuit gain, the gain value will increase.  Quiescent current depends on the power of R7, R8, when its value…

Full Power Mobile Phone Jammer Circuit Diagram

Full Power Mobile Phone Jammer Circuit Diagram.To day if we are talking about expert Cell phone Jammers we are conversing about this schematic underneath. First off all you should be very very cautious how to use this apparatus. Its completely illegal and so the reason. I post this Circuit is only for educational and testing causes. This type of apparatus is being utilised by security for VIPS, particularly at their limousines to avoid blasting device initiating while the vehicle passes from the goal cell phone-bomb. Off course there are those who use it to make a antic or to make the persons crazy in the rectangle block you are.
The power of the jammer is currently sufficient to do your thing, but certainly you can place a 30W linear power amp at the RF output and impede a much wider locality. So, Be pleasant individual with that and recall that there are people who may need desperately to obtain or make a call and one of them could be you! And if you can't oppose of functioning …