# Yearly Archives: 2014

## Wireless Receiver Sensitivity

Receiver sensitivity is defined as the minimum signal power (Pi,min) at which a receiver can detect a signal while providing an adequate SNR at analog receiver output (BER at digital receiver output). This is minimum detectable signal(MDS) power. In a multi-standard receiver, the sensitivity requirements vary depending on mode of […]

## Resistive Terminated LNA

Well suited topology for broadband LNA design. Schematic of the LNA with resistive termination is shown in Figure 1(a). The resistive termination() at the input provides broadband impedance matching over a wide frequency band. The equivalent circuit of resistive termination LNA is shown in Figure 1c. Gain of LNA, […]

## Ampere’s Law

Ampere’s law relates the integrated magnetic field around a closed loop to the electric current passing through the surface of the loop. It was first discovered by André-Marie Ampère in 1826, later re-derived by Maxwell using hydrodynamics in 1861. Now it is one of the Maxwell equations, which is the […]

## Equivalent Noise Bandwidth 1 comment

Equivalent noise bandwidth(ENBW) is defined as the bandwidth of a brickwall filter which produce same integrated noise power as that of an actual filter. This is also refered to as noise bandwidth or effective noise bandwidth. Given a filter with transfer function , the equivalent noise bandwidth () is defined […]

## Coupled Inductors as Transformer

Figure 1 shows a pair of coupled inductors with self inductance and , magnetically coupled through coupling coefficient . For the dot notation shown in Figure 1, the equations that relate terminal voltages and terminal current in frequency domain are given by, (1) where is the mutual inductance between […]

## Noise Figure of an Attenuator

Consider an attenuator as shown in Figure 1, whose conversion loss is . Assume that input and output ports are perfectly matched and the attenuator is in thermal equilibrium with its surroundings. Noise power at the input of attenuator due to a perfectly matched source at temperature() is given by […]