Activity for jm567
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #280921 |
Hello, and thanks for the reply. When I connect the S11 to the input of my amplifier, does the output end have to be terminated or would I just leave it open? I will try this tomorrow since it is getting late tonight, and post my findings. (more) |
— | about 3 years ago |
| Edit | Post #280915 | Initial revision | — | about 3 years ago |
| Question | — |
Measuring Input/Output Impedance with a VNA On paper you can measure the input impedance of an amplifier circuit by attaching a voltage source to the input, shorting the output, and calculating the resulting impedance from the voltage and current, or vice versa to find output impedance. But how would I measure ... (more) |
— | about 3 years ago |
| Edit | Post #278522 | Initial revision | — | over 3 years ago |
| Question | — |
General Questions Regarding FPGAs I'm curious about FPGAs and would eventually like to get into them sometime during the future, so I'd like to ask three broad questions to help orient myself: 1. In what applications are FPGAs the most popular? 2. With respect to RF and wireless designs, how are FPGAs typically utilized? 3. ... (more) |
— | over 3 years ago |
| Comment | Post #278519 |
Thanks for the response. Always good to validate my ideas with people more experienced. (more) |
— | over 3 years ago |
| Edit | Post #278513 | Initial revision | — | over 3 years ago |
| Question | — |
Emitter Bypass Capacitor in a CE Amplifier How exactly is the emitter capacitor C3 helping to increase the voltage gain in the common emitter amplifier below? Is it because for AC signals the emitter looks like a short to ground and that essentially increases the voltage drop across the collector resistor? Thanks. (more) |
— | over 3 years ago |
| Edit | Post #278445 | Initial revision | — | over 3 years ago |
| Question | — |
Filter Impedance Consideration In a lot of textbooks, filters seem to be designed around a matching source and load impedance. However, If I have a filter stage between an antenna and an LNA, wouldn't I want the load impedance(input to the LNA) to be large with respect to the source(antenna) in order to not attenuate the signal ev... (more) |
— | over 3 years ago |
| Edit | Post #278378 |
Post edited: |
— | over 3 years ago |
| Comment | Post #278380 |
Okay. In this case would the BFO still be a tunable 7MHz - 7.3MHz oscillator since that is the range of carrier wave to be re-inserted? Or is it a totally fixed frequency across the entire spectrum? Thanks. (more) |
— | over 3 years ago |
| Edit | Post #278378 | Initial revision | — | over 3 years ago |
| Question | — |
Mixers and Audio Extraction in a DCR Architecture I want to make a simple 7MHz direct conversion SSB receiver in order to materialize some RF concepts I have been teaching myself lately. My question revolves around the mixer portion. I'm failing to understand how the audio is extracted from the carrier wave. Lets suppose I want to listen to an ... (more) |
— | over 3 years ago |
| Comment | Post #278346 |
Yup, you nailed the circuit based on my description. This clears things up alot. Thank you. (more) |
— | over 3 years ago |
| Edit | Post #278341 |
Post edited: |
— | over 3 years ago |
| Edit | Post #278341 | Initial revision | — | over 3 years ago |
| Question | — |
Purpose of emitter resistor in a common collector amplifier I see a lot of common collector amplifiers with the output taken across an emitter resistor. What is the purpose of doing it this way instead of connecting your load directly to the emitter? I should mention that I am referring to an emitter follower biased by the collector output of a previo... (more) |
— | over 3 years ago |
| Edit | Post #277992 | Initial revision | — | over 3 years ago |
| Question | — |
Antenna Feed Line Question Hello, I am designing 1/4 WL strip antenna for a bluetooth chip and i had some questions regarding the 50 Ohm feed line. Right now I am using a Nordic-recommended 1.5mm trace width and a 23mm + 4mm(for tuning purposes) trace length as my antenna. My feed line is 2mm away from the antenna and th... (more) |
— | over 3 years ago |
| Comment | Post #277853 |
Thank you, this was very clear. (more) |
— | over 3 years ago |
| Edit | Post #277846 | Initial revision | — | over 3 years ago |
| Question | — |
Current Flow in the OFF Time of a Switching Power Supply I am having a difficult time picturing the flow of current and the role of the capacitor during the OFF time of a buck converter. Here is my understanding so far. During the ON time the magnetic field of the inductor grows and positive charge is being stored on the top plate of the capacitor as well ... (more) |
— | over 3 years ago |
| Edit | Post #277845 | Initial revision | — | over 3 years ago |
| Question | — |
LC Filter and Capacitor Considerations I've been experimenting with LC filter circuits on the output of a SMPS I recently bought because it was too high for the circuit I'm making. After hooking up many different combinations, I found that this PI filter worked best for my load: LC PI Filter I'm trying to understand why this worked ... (more) |
— | over 3 years ago |
| Comment | Post #277419 |
Thanks for the reply. I always wondered about the solid layer 3 power plane concept that some people touted but didn't know any better since I recently started. I see it's better to view 3 as a last resort backup when 1 & 4 is overrun with signals or 1 has no more room for power. (more) |
— | over 3 years ago |
| Edit | Post #277418 | Initial revision | — | over 3 years ago |
| Question | — |
4-Layer PCB Routing Question I am designing a 4-layer PCB that has both analog and digital circuitry throughout it. The analog section involves high return currents as well as ADCs sampling the voltage across sense resistors among other things. The digital side does not have high-frequency communications - PWM at 25kHz, and a Tw... (more) |
— | over 3 years ago |
| Comment | Post #277401 |
Thank you for the clear explanation. Visualizing the IC as the current source made everything suddenly click. (more) |
— | over 3 years ago |
| Edit | Post #277391 | Initial revision | — | over 3 years ago |
| Question | — |
Bypass Caps and High Frequency Current Return Path I was watching this video by w2aew on the function of ceramic bypass capacitors, and at 6:00 he states that high-frequency currents take the path of least-impedance and make their way to the power rail through the ceramic capacitor next to the IC. Okay, so I get the fact that the high frequency c... (more) |
— | over 3 years ago |