RF-sampling ADCs for multiband receivers
Signal Chain Basics 7/24/2018 3 comments
High-speed data converters can now digitize or generate signals directly at radio frequencies (RFs), replacing traditional RF components such as mixers and local oscillators (LOs) with digital processing
Image Reject Mixers Demystified
Signal Chain Basics 6/1/2018 1 comment
The need to translate frequencies up or down is a basic signal-chain need. The key component used to do this is the mixer, which essentially multiplies two signals together
Signal Chain Basics #133: Designing summing active filters
Signal Chain Basics 2/22/2018 1 comment
In this article, Iíll describe a few easy steps that will convert any Sallen-Key (SK) or multiple feedback (MFB) active filter from a single-input filter to a summing active filter that gives the same response without difficult calculations or analysis
I2C switches: a closer look
Signal Chain Basics 1/16/2018 Post a comment
Despite this reputation, I2C does have its challenges: a limited number of bits for a unique address can create address conflicts, or multiple devices may require different input voltages. Although solving these problems may seem straightforward, there are implication challenges to consider
Signal Chain Basics #131: RF-sampling DACs for multiband transmitters
Signal Chain Basics 1/2/2018 Post a comment
High-speed data converters now digitize or generate signals directly at radio frequencies up to several gigahertz, replacing traditional radio-frequency (RF) components like mixers, local oscillators (LOs) and amplifiers. This article focuses on the transmitter (downlink) using an RF sampling digital-to-analog converter (DAC); my next article will cover the receiver (uplink)
Signal Chain Basics #116: Combining signals for better performance
Signal Chain Basics 9/13/2016 2 comments
When the phase noise performance is just not good enough, one possibility is to combine two or more signals that are in phase to generate a better phase noise signal. This concept applies to the scenario of combining two sides of a differential output to form a single-ended output or the combination of signals from two semiconductor chips of the same type and configuration.
What is low-side current sensing?
Signal Chain Basics 11/5/2015 4 comments
A quick reminder, low-side current-sensing is where the sense element, or shunt resistor, is placed in series with the load between the load and ground
Common-mode voltage for industrial transceivers
Signal Chain Basics 9/29/2015 1 comment
Most differential field bus technologies, like CAN and RS485, specify a parameter called common-mode voltage. Common-mode voltage refers to the range of bus input voltages, with respect to the transceiverís ground, within which the transceiver maintains consistent input receiver thresholds.
SIGNAL CHAIN BASICS (Part 103): Integer Boundary Spurs
Signal Chain Basics 7/9/2015 Post a comment
The phase-locked loop (PLL) in Figure 1 works by starting with a stable input frequency (fOSC). It is divided down by R to get the phase detector frequency (fPD), then multiplied by N to get the voltage-controller oscillator (VCO) frequency (fVCO). Finally, it is divided down by D to get the output frequency (fOUT). The output divider, D, is typically an integer, but it is possible for the N divider to be fractional. Devices can exist with multipliers on the input path, effectively making R fractional.
A three-part series of articles explains how to minimize interference through proper PCB design and layout.
In such things as laboratory power supplies or electronic systems, in which various components are connected to longer cables, the regulated voltage is not always particularly accurate at the point where it is needed due to various voltage drops across the interconnection lines.
There area plethora of USB Type-C articles out there, but this is the first one I have seen with a really neat design architecture to shrink the board footprint with a high level of integration.
The required selectivity of a customer design implied four-pole filters with about 10% bandwidth (passband width about 10% of the centre frequency). There was a catch---a tight power budget
Monitoring the heart rate or blood pressure in order to enhance the quality of their life, this is known as Remote Patient Monitoring (RPM)