For discussions regarding SATCOM uplink, read here: Link budget calculations for SATCOM – Uplink This post explains the mathematical equation used to calculate the SNR of SATCOM downlink, or in other words, SNR of satellite signal as received at ground terminal. …
Gain Method: Noise Figure (NF) can be measured, with a spectrum analyser, by using a procedure called Gain-Method. Note that following condition needs to be met by the Device-under-Test (DUT) for correct measurement: DUT (e.g., Receiver) output noise floor should …
In the previous blog, we discussed about the first drawback of the Heterodyne transmitter which is DC offset. The second drawback is Mixing Spurs, which will be discussed in this blog. What is Mixing Spurs? In simple language, if there …
Heterodyne Transmitter Heterodyne Transmitter is a two-step upconversion, just like heterodyne receiver which is a two-step downconversion. Read about the heterodyne receiver. This structure involves two steps of mixing and there is no oscillator pulling problem, however, just like other …
In this blog, we will explore individual Phase-Nosie contributors in a Phase-Locked Loop, how they get shaped by closed loop, and how they combine to produce typical Phase-Noise profile of a PLL. This fundamental understanding is vital in optimizing Phase-Noise …
In the previous blog, we discussed about what is Oscillator Pulling. Oscillator Pulling can be explained from another point of view. If a sinusoid at the frequency of w1=wLO+∆w is injected into the oscillator operating at the frequency of wLO …
What is oscillator pulling and how is it generated? One of the problems faced while designing a transmitter is Oscillator Pulling or sometimes called Injection Pulling. The output power of a power amplifier is very high which we already know, …
What is linearity? Linearity is the property of a mathematical relationship or function, which can be graphically represented as a straight line. Linearity can be graphically represented as a straight line. We always expect to have this kind of outputs …
This blog talks about the carrier leakage within the transmitter. The analog base circuitry producing the quadrature signals in a transmitter exhibits DC offset. What is DC offset? DC offset is coming from local oscillator leakage. The local oscillator leakage …
In this blog we will discuss about the challenges faced in designing RF transmitters, focusing on direct conversion transmitters. I/Q mismatch What is an I/Q mismatch? We have already discussed this before in receiver blogs and read about I/Q mismatch. …