Extension state : BA ME. Kind code of ref document : A2. Kind code of ref document : A3. Effective date : Disclosed herein are power detectors and methods for detecting the average power level of an RF input signal and the voltage envelope of the RF input signal. Also disclosed herein are linear envelope detectors and methods for detecting the voltage envelope of an RF input signal.
Provisional Patent Application Serial No. The present application relates generally to root mean square RMS detectors and envelope detectors.
There are many applications in which it is desirable to measure the average power level of a radio frequency RF signal. For example, power measurement and control of RF signals in both the transmitting and receiving chains of modern wireless communications systems, such as cellular telephone networks, may be essential.
These complex modulated signals have a time varying crest factor, which is defined as the peak to average power ratio of the signal. Intolerable errors can result if conventional power detectors using diode detection or successive amplification are used to measure the signal power. Another challenge in modern wireless communication systems is improving the power efficiency of power amplifiers used in the transmit chain.
Efficient use of power amplifiers is important in mobile communications systems. Improved power efficiency can provide significant benefits including lower overall operating costs. To improve power efficiency, it is known to apply envelope tracking to the power amplifier input signal, and to use the detected envelope to vary the amplifier operation.
For supplying power to the power amplifier, a variable power supply is utilized in an envelope tracking system. The input signal envelope power levels are monitored using an envelope detector, and the power that is supplied to the power amplifier is varied based on the monitored envelope levels. In particular, the supply voltage supplied to the power amplifier is varied so as to be just sufficient to reproduce the power level required by the amplifier at a given instant of time.
Accordingly, at low envelope power levels, a low supply voltage is provided to the amplifier, and the full supply voltage is only provided when the maximum output envelope power is required, i. RMS power detectors can precisely measure RF power independent of the modulation type signal shape or crest-factor. Accurate RMS calculation of these complex modulation schemes requires long integration times to include the time-varying envelope in the measurement.
Thus, commercially available RMS power detectors are generally not capable of providing the envelope level of the modulated signals.
Therefore, for transmitter systems, it is desirable to have a power detector that provides both average power information and input voltage envelope information. A power detector in accordance with one or more embodiments includes a logarithmic RMS detector, a gain or attenuation element, and a linear envelope detector.
The gain or attenuation element also receives the RF input signal and generates an amplified or attenuated version of the RF input signal. The linear envelope detector receives the amplified or attenuated version of the RF input signal and detects the voltage envelope of the RF input signal, wherein the gain or attenuation element can generate a selected amplified or attenuated version of the RF input signal to shift the operating range of the envelope detector to higher or lower power levels.
A method of detecting power of an RF input signal in accordance with one or more embodiments comprises the steps of detecting the average power level of an RF input signal using a logarithmic RMS detector; generating an amplified or attenuated version of the RF input signal; and detecting the voltage envelope of the RF input signal using the amplified or attenuated version of the RF input signal, wherein the amplified or attenuated version of the RF input signal is selectively generated to shift the operating range of the envelope detector to higher or lower power levels.
A power detector in accordance with one or more embodiments includes a logarithmic RMS detector and a linear envelope detector.IRIS provides management of, and access to, observed and derived data for the global earth science community. Our mission is to advance awareness and understanding of seismology and earth science while inspiring careers in geophysics. IRIS staff and subawardees oversee the construction, operation, and maintenance of seismic networks and related data facilities utilized by a wide sector of the earth science community.
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RMS envelope. I could not find any description about RMS. Anyone can help me please?
Peak power vs log and envelope detector
Milton Plasencia. Re: RMS envelope. Hi, In sac exits the commands envelope and rms separately.For me it is important the temperature behaviour, the linearity and the slope to have more mV per dB.
LTC is a good choice for HF. An LTspice model exists, which helps the designer choose the best detector capacitor values for the RF and modulation frequency ranges.
Temperature compensation is internal. Regardless of the IC or detection method, the system should incorporate a provision for in-system calibration of the detector. Regarding ADL, it has digital comparator output which would indicate that a specific peak power has been exceeded. Also, the pin 3 VCAL output is available which precedes the comparator. Log in. Site Search Log in.
RF and Microwave. RF and Microwave requires membership for participation - click to join. Share More Cancel. Peak power vs log and envelope detector. Reply Cancel Cancel. Hello Cste, ADL has comparator output, which may not be desirable for this application.
LT is very sensitive, requiring shielding to attenuate RFI from cell phones, etc. The ADC must be fast enough to sample and measure the detector output accurately. This is the preferred approach, because of the flexibility and programmability. Thanks a million, but the LTC has a not so linear behaviour. It would need multi-point calibration. Best regards, Bruce.
This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.
Also disclosed herein are linear envelope detectors and methods for detecting the voltage envelope of an RF input signal. USP true USB2 en. EPA3 en. CNB en. TWIB en. Self-calibration and compensation of detector offset in GSM transceivers power control loop. Method and system for robust symmetrical number system photonic direction finding. Low-voltage bipolar OTA having a linearity in transconductance over a wide input voltage range.
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USB1 en. CNY en.The correct answer is B. Thank you for your help, Sally. Sally, I racked my brain a bit and I think I can point you in the right direction. First, you helped me catch a typo on question 6. I'll have to fix that. Unfortunately, that's not going to help you. I also believe the other question you have deals with question 14 vice You would be correct if we were dealing with "simple" power and voltage.
Unfortunately, the question is looking for Peak Envelope Power PEP which is the average power a transmitter sends to the transmission line. This deals with a signal's sine wave and goes a bit beyond Ohm's law and the power equation.
Because the sine wave is not sending a constant stream of power throughout the entire wavelength, to make the PEP calculation you need to determine the average power over the course of the wavelength. To determine the average power, you need to determine the peak envelope voltage, multiply it by the 0. For Question 14, you can use the same formula as in question 6.
I just added the RMS equation for what I thought was going to be necessary for later explanations. The formulas for 6 and 14 are essentially the same. Hope that helps. Thank you, Andy. That's exactly what I was doing. I still haven't been able to make the formula work. I'm not giving up. The good news is, I've definitely memorized the answer trying to figure out how to get to it. Thank you for a quick answer. Hey Andy, it's am and I'm cramming for my General Class which is in less than 8 hours.
Anyway I noticed that in the material for Q6 you have the formula for PEP written and spoken incorrectly the second time you mention it, more towards the end of the slide although it is correct earlier.Documentation Help Center. Create a double sideband amplitude-modulated signal. The carrier frequency is 1 kHz.
The modulation frequency is 50 Hz. The sample rate is 10 kHz. Extract the envelope using the hilbert function. The envelope is the magnitude of the analytic signal computed by hilbert.
Plot the envelope along with the original signal. Store the name-value pair arguments of the plot function in a cell array for later use. The magnitude of the analytic signal captures the slowly varying features of the signal, while the phase contains the high-frequency information. You can also use the envelope function to generate the signal envelope directly and modify the way it is computed.
For example, you can adjust the length of the Hilbert filter used to find the analytic envelope. Using a filter length that is too small results in a distorted envelope. You can generate moving RMS envelopes by using a sliding window. Using a window length that is too small results in a distorted envelope.
Using a window length that is too large smooths out the envelope. You can generate peak envelopes by using spline interpolation over local maxima separated by an adjustable number of samples.
Spreading out the samples too much smooths the envelope. Increasing the peak separation parameter can decrease the effect of spurious peaks due to noise. Introduce random noise to the signal. Use a 5-sample interval to see the effect of noise on the peak envelope.
It only takes a minute to sign up. I'm using the following code to reproduce the behavior of envelope :. However the first option blue line is displaced about 50 samples compared to the second option red line :. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Ask Question. Asked 2 years, 6 months ago.
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Thread: RMS envelope
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