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Multipath Diode Power Sensors vs Thermal Power Sensors for Modulated Signals

I am often asked about measurement of modulated signals using diode sensors / meters. There is a view that Thermal Power Sensors / Meters are more accurate than Diode Power Sensors / Meters when it comes to measuring modulated signals. There is a trust in the industry that drives this – of course, heat dissipated in a resistor is an absolute measurement of power. From an R&S perspective our thermal sensors (NRP-Z5x series) are able to get the match so good that our linearity is proven to the be just about the best there is with a thermal power sensor in the market today.

Within the square law region the detector provides a linear relationship between incident power and output signal. The detector works as an RMS (voltage) rectifier and delivers a signal that is proportional to the average RF power. Outside the square law region the relationship is non-linear and this causes the problem if you cannot compensate these non-linearities in real-time anymore.

Even if the sensor is a multipath device with switches – during the switch points, this can cause distortion and large in-accuracies in the switch points. A diode sensor should give a good average result, but like the Thermal sensor it will not track the envelope (rise / fall time etc). This is a topic for a different post! R&S multipath diode sensors have a patented design that does not include switches for each power range. All ranges are measured simultaneously and a soft weighting is applied to each path. Effectively the switch linearity can be corrected so the whole sensor is operating in a linear fashion.

Continue reading » » Multipath Diode Power Sensors vs Thermal Power Sensors for Modulated Signals

Posted in Test and Measurement

R&S UK and NPL to host Advanced Power Measurement Seminar

On 23 November 2011 R&S and NPL (National Physical Laboratories) will host a power measurement seminar at NPL’s high tech facility in Teddington, Middlesex. NPL are known as the UK authority in accurate power measurements.

Rohde and Schwarz were the first to introduce USB power sensors to the market and hold patents in the design of both thermal and diode power sensors making them the most accurate on the market.

The seminar will be headlined by Head of Power Sensor development at Rohde and Schwarz, Mr. Thomas Reichel who will discuss the technical challenges of designing sensors to make accurate power measurements at and above 50GHz.

A full agenda can be found here.

Register for the free seminar here.

Continue reading » » R&S UK and NPL to host Advanced Power Measurement Seminar

Posted in Events & Conferences, Test and Measurement

EngineeringTV interview for the R&S FSW

Interview with EngineeringTV (Microwaves&RF magazine) at European Microwave 2011 for our new R&S FSW high end spectrum analyzer. Serious receding hair line and slight scouse accent (brought up on the border between Manchester and Liverpool).

Posted in Events & Conferences, Test and Measurement

Photographs from European Microwave 11 to 13 October 2011 – Manchester

Some photographs of the R&S stand at the European Microwave exhibition. As I manage to sort through more images I will add them to the gallery.

Outside Link: Microwave Journal’s Pat Hindle – Photo’s from European Microwave

Posted in Events & Conferences, Test and Measurement

The highest performance spectrum analyzer ever – R&S FSW

When we talk about spectrum analysis what do we consider the most important aspects? Normally it depends on whether your background is based on time domain (scopes) or frequency domain measurements.

The scope guys will tell you bandwidth is everything so you can see the smallest glitch in a time domain signal. If you want to inspect all the detail possible in the frequency domain a spectrum analyzer is really the only tool you really should be using.  The frequency domain guys will tell you its all about dynamic range (spurious free dynamic range) and phase noise performance.

Without these aspects it is not possible to get the detail required on the smallest spurs that may be created in a device under test. Or to characterise distortion performance of amplifiers with precision. Scope A/D converters have very wide bandwidth but do not have the resolution or spurious free dynamic range required to create an accurate picture of spurious and other phenomena in the frequency domain.

With this in mind, R&S has released what is seen as the highest performance spectrum analyzer ever to the market and below is an overview of what makes it so high performance, and why it is important for measurement tasks in the frequency domain.

R&S FSW Performance Overview – all the important points that make it the highest performing spectrum analyzer ever

Continue reading » » The highest performance spectrum analyzer ever – R&S FSW

Posted in RF and Microwave News, Test and Measurement