Questions tagged [tuning]

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1 answer
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Analog television: What is the difference between the first IF and second (demodulated) IF?

I am trying to understand what kind of changes occur to a signal in the chips which sit between the tuner and, for example the FM audio demodulator. Take the attached example - the TDA2546A. It takes ...
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0 votes
1 answer
91 views

Resonant RF transformer using a piece of wire (no capacitors)

I'm curious if it is possible to build a spark-gap Tesla coil without using capacitors at all. Basically, treating the primary and secondary as TX/RX antennas and cutting them to proper length so that ...
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-1 votes
1 answer
49 views

VCO tuning voltage range starting from higher than 0 V

I have seen some VCO datasheets. In every datasheet, I see that the tuning voltage range starts from some value above 0 V (like 0.5 V, 1 V etc). So, what would be the frequency at 0 V? And why do they ...
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  • 49
0 votes
4 answers
176 views

Difference between tuning and matching for transmitter/receiver circuits

I would like to find a coherent answer to following question: What is precisely the core difference between tuning and matching in HF electronics, especially in design of transmitter/receiver circuits?...
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0 votes
0 answers
41 views

Tuning the resonance frequency using varactors in a RCL circuit (and how to avoid noise)

I'm a physics student trying to run a few simulations on a RCL circuit. I don't have too much experience with electronics and could use some help on some basics on how to tune the resonance frequency. ...
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0 votes
1 answer
49 views

DDS - find optimal size for LUT, PHACC and sampling freq for application

I had the following question. About the topic of DDS you can find a bunch of information on the net and i think i understood the basics relatively well. You use a lookup-table with stored values of ...
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0 votes
3 answers
124 views

Old tvs, how did storing settings work, and what changed in the tv when we tuned a channel?

I don't have an EE background, but I would like to understand some aspects of old TVs. When we tuned channel what exactly changed inside the tv. Was there a circuit card in the tv where something ...
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1 vote
1 answer
140 views

How does one choose a resistance for an AM radio antenna receiver tuner?

[![enter image description here][2]][2] I am using some pretty rough, brute force and novice calculations, so if anyone knows a nicer method I am happy to learn. I want to build an AM radio receiver ...
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0 votes
2 answers
301 views

Variable Capacitor - capacitance vs. rotation angle

I have an Elenco AM / FM radio kit. For the AM section I am trying to figure out the relationship between the frequency shown on the calibrated dial and the angular position of the dial. For a ...
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  • 387
0 votes
1 answer
72 views

Calculating lengths of single-stub transmission line when all 3 characteristic impedances differ

Consider a transmission line circuit like the following but where \$Z_{o2}\$ was also unique (say \$Z_{o2}=7\,\Omega\$): I know how I would find \$l_1\$ and \$l_2\$ using smith charts: $$Re\left\{Y_n(...
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  • 155
1 vote
0 answers
131 views

How to design a PI controller for fourth-order transfer-function?

Fourth-order systems may render very complex characteristic equation that are difficult for tuning. Is there any method to tune controllers for these systems easily?
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5 votes
2 answers
322 views

Why do AM radio stations have secondary frequencies?

First thing I'm sorry if this question sounds too much beginner-ish. I don't major in electrical engineering so I may lack the basic knowledge. I have been noticing that, while tuning my AM radio, ...
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  • 151
0 votes
2 answers
174 views

Antenna Tuning for Source Impedance not equal to 50 Ohm

I have designed a setup for 433.92MHz wireless device (a key fob). The source impedance is not equal to 50Ohm. The load impedance may or may not be 50Ohm depending upon the choice of the antenna. For ...
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  • 141
0 votes
0 answers
28 views

RC quality factor increase

simulate this circuit – Schematic created using CircuitLab This circuit has a bandwidth of 0.9Hz but I want even lower bandwidth. I have this RC tuning circuit. If i had an RLC tuning circuit ...
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1 vote
0 answers
50 views

Tuning PID Controller with high precision

I'm learning control theory at university and I have to design PID controller for this object G(s) = 10/s(s+1); But my teacher requires settling time <10s and %overshoot <=2% Anyone can suggest ...
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0 votes
2 answers
137 views

Antenna Tuning for a Multi-band Antenna

I have PCB antenna . which support multiple band antenna. https://www.johansontechnology.com/datasheets/0830AT54A2200/0830AT54A2200.pdf we also have tune circuit before antenna as recommended by ...
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  • 682
2 votes
1 answer
225 views

RF Jumper at 2440MHZ

I need a series component to isolate a 2440MHZ antenna for testing purposes-- it can either be a a high quality 0402 RF capacitor (Johansen) or a zero ohm resistor. The series component will remain ...
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  • 135
1 vote
3 answers
197 views

Radio tuning capacitor

In a radio tuning capacitor that consists of semicircular plates , are the plates connected in series or in parallel ?
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1 vote
1 answer
417 views

Antenna tuning & impedance matching, do i need to connect the IC?

I want to make a pcb rf trace to use it as an antenna, for a bluetooth IC. I have already studied the basics of impedance matching and antenna tuning, smith chart and antenna clearance. The specific ...
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0 votes
0 answers
258 views

Can I replace the transistor in this circuit (Esaki oscillator) with a Zener diode?

Can I replace the transistor in this circuit (Esaki oscillator) with a Zener diode?
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1 vote
1 answer
92 views

Do algorithms exist for tuning microwave filters?

I'm a systems engineering student and I have taken a summer job at a company that manufactures various microwave filters, my role is to "try" improve and standardise their processes in order to ...
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-2 votes
2 answers
92 views

My antenna tuning component values worked on a fresh board previously. Now they're not working. What could be causing this?

This is one of those hardware questions that's making me bang my head against a wall. About six weeks ago I spent a day tuning the NFC antenna on my board. I ended up using ~71pF of shunt capacitance ...
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0 votes
0 answers
28 views

Finding the gain difference for a ultrasonic assembly

I am tuning an ultrasonic assembly for a welding application and tuned the system to operate at 41kHz according to the oscilloscope. The transducer operates at 40kHz, when calculating the gain with ...
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  • 273
6 votes
1 answer
697 views

Where to connect the VNA during matching network tuning

I'm trying to design the matching network between an antenna and its transmitter, running at 868MHz, as shown below. There's probably about 20mm between the transmitter output and the Pi network. ...
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  • 1,268
0 votes
0 answers
57 views

MOSFET Switch for Tuned LC Tank

I am trying to implement the circuit as shown below. I essentially want to be able to control the gate voltage of the NMOS to change the resonant frequency from 5GHz to 2.5GHz. For a transistor size ...
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1 vote
0 answers
388 views

Magic Eye Tuning Tube Variable Negative Voltage

I am thinking about several applications of magic eye tuning tubes as display pieces and had a question about their operation. I have attached a sample circuit from a datasheet for an EM84 tube. I ...
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0 votes
1 answer
140 views

Some questions regarding impedance matching and tuning

For maximum power transfer in a circuit impedance matching is performed: Similarly from the transmitter antenna to the receiver/load one can think the total impedance from antenna to the receiver as ...
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