Questions tagged [low-noise-amplifier]

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2
votes
1answer
189 views

What's the catch with these JFETs?

I'm designing a low-noise, high-bandwidth (100 MHz) pre-amp using JFETs. The choice for JFETs was because it needs to operate with large source impedances (>10 kΩ). I spent a while looking for a ...
2
votes
1answer
183 views

Origin of increased noise in BF862/OP27 charge amplifier

For the amplification of piezoelectric sensor signals I am currently building a charge amplifier with a low noise JFET frontend utilizing an NXP BF862. The amplifier design is based on application ...
1
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1answer
52 views

Matching Networks on Narrowband Multistage Low Noise Amplifier (LNA)

How does the inter-stage matching network of a narrowband LNA compare to that of a wideband LNA for the same multistage design? I've read somewhere that narrowband LNA does not necessarily require a ...
0
votes
1answer
195 views

Effects of impedance mismatch on RF signals from antenna

I'm building an antenna array that operates at high frequencies (around 2 GHz). I want to use a SDR dongle that has a 75 ohm input impedance as receiver, I've also bought the coax cable, a 4 way ...
3
votes
2answers
87 views

Why voltage source has been connected via inductor at the output of LNA?

I have been reviewing the schematics of LoRaWAN Gateway designed by Microchip (Page 48). The output of the LNA has been connected to voltage source via inductor. ...
2
votes
2answers
195 views

Low-pass Filter with zero drift amplifier

Can an auto-zero or chopper amplifier be used in a low-pass filter to remove a high frequency carrier? I am trying to design an active low-pass filter with a 1kHz cutoff and very low DC drift, offset, ...
1
vote
4answers
208 views

How to amplify RF signal to high enough level for a CMOS downconverting mixer?

I've been reading original academic papers on mixers and now a RF textbook and I have been unable to understand a very basic thing, which is how do I get a RF signal, say -65 dBm, at a high enough ...
0
votes
2answers
118 views

How may noise voltage and noise figure be compared?

For instance, comparing the MIC920 and the BGA2818, it's expected that since the latter is intended for application as an RF LNA and the former is general-purpose, the BGA2818 would out-perform the ...
2
votes
1answer
120 views

Antenna preamplifier design for ELF Schumann resonances receiver

I'm interested in listening to extremely low frequency band below 100Hz, where the famous Schumann resonances reside. I will use a large T shape antenna together with a very low noise, very high ...
1
vote
1answer
148 views

Use Raspberry Pi to power a low noise inverting amplifier with negative voltage input

I am looking to use a Raspberry Pi to power and read the current from a current-to-voltage converter. I am currently using two batteries to power the operational amplifier, as shown in the schematic ...
0
votes
2answers
92 views

Multiband LNA Design [closed]

I am familiar with circuit design - Basic Op-Amp Design, concepts like stablity, Phase margin and I am a beginner in Microwave Engineering. I am familiar with some basic ideas and little familiar with ...
0
votes
1answer
54 views

Using an RF adapter to improve LTE signal in the house

In my apartment, the GSM signal is very scarce, if not absent at all, except for a few spots, where there's a decent LTE signal and I can browse internet reliably. In order to improve the reception ...
0
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0answers
143 views

how should i do to plot noise figure in cadence virtuoso?

I'm designing a cascode common-gate LNA. I use "SP" analysis to plot the noise figure. The noise figure is 1.8 dB at the frequency of interest, 2.4 GHz, which is impossible, so I want to know what's ...
0
votes
0answers
158 views

LNA using Common Emitter with feedback collector

I am trying to design an LNA with input impedance of 50 Ohms, I am considering the topology illustrated below. I have found an online calculator that computes this however when I try to work out the ...
1
vote
1answer
127 views

Inconsistent Gain with Instrumentation Amplifier

I'm trying to prototype an instrumentation amplifier with OPA2111 as the first stage and INA105 as the second stage on a breadboard. The circuit diagram is similar to this: Power rails are connected ...
5
votes
1answer
113 views

Microphone Amplification

I am working on a project using a microphone/microcontroller combination to detect if a clap has occurred. Thus far, I am using the Electret Microphone Amplifier - MAX4466 with Adjustable Gain from ...
1
vote
3answers
287 views

Monitor tiny variation in voltage

I should apologize if my question is trivial since I did not find a similar question, I decided to specifically ask mine. I have a microscopic membrane in my lab, this piece which we call it NMS has ...
1
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3answers
143 views

Low noise amplifier DC gain

This circuit provides 30dB gain to a 100kHz signal with a 10k input impedance. Is capacitor C2 necessary to suppress DC gain or is it redundant with the AC coupled input? I would also like to make ...
0
votes
0answers
41 views

Need help understanding a fairly vague solution to example problem (the topic is noise in CMOS circuits)

So I have the solution to the following example problem I am working on: Now the issue is that I am trying to understand the solution I was given: The thing is this solution is simply quite vague. ...
5
votes
1answer
151 views

Electrochemical Measurements Using Lock-In amplifier

I'm trying to measure small electrochemical signals using a trans-impedance amplifier fed into a lock-in amplifier. I have an electrochemical cell that poses a very high impedance (100s of MegaOhms) ...
1
vote
1answer
131 views

Ιnput referred noise of an amplifier

I have a problem with a low noise amplifier because I can't find in ADS(Advance design system) software how to integrating under the are of a measured curve in a specific frequency range.Can someone ...
2
votes
1answer
238 views

MMIC RF Amplifier BGA2817 vs. Discrete Transistor/s Amplifier?

I've been working on learning transistor 101s, for a 900MHz transmitter. I'm to the point, I can work the basic algebra, and intuitively understand changing the passive components in the transistor ...
0
votes
2answers
126 views

Is Gain Block can be used a Power Amplifier

I have chosen 2 datasheets of MMIC Power Amplifier: HMC311ST89 MMIC AMPLIFIER – DC-6GHZ -16db Gain HMC637ALP5E – DC-6GHZ – 13db Gain My intention is to use the 1st one as Power Amplifier. I was ...
0
votes
3answers
311 views

Amplify coil antenna signal

Suppose I have a coil antenna that receives an ideal 100kHz ~200uVpp signal which I would like to measure. Can this signal be amplified to 2Vpp (10,000x gain) with 1% error for moderate cost (< $...
0
votes
3answers
104 views

Optimizing dynamic range for acquisition of noisy signal

Is there a good rule of thumb for setting the gain of a noisy signal before digitization? Say I have a 16-bit ADC with a ±1V range; to what level should I amplify the noise floor of my signal relative ...
6
votes
2answers
1k views

How to design wide band amplifiers?

I've been designing microwave power amplifiers and LNAs for school, I design in microstrip and my matching networks usually consist of stub/line sections or similar arrangements, I have also designed ...
4
votes
1answer
551 views

What type of transistor generally has the lowest flicker noise?

How do BJT vs JFET vs HBT compare in terms of \$1/f\$ noise amplitude and corner freqency? I know these transistor types are very different, used for different frequencies and powers, and each have ...
1
vote
2answers
88 views

Noise performance at cryogenic temperature

I want to know what kind of improvemend electronic circuits get at cryogenic temperatures.I looked at online noise calculator and it shows that if I go from room temperature to 1 kelvin the noise ...
1
vote
1answer
81 views

RF (2.4GHz) LNA board with multiple amplifier stages: Should I use multiple voltage regulators?

I'm working on a LNA board to work in the 2.4GHz band. I'm using broadcom/avago MGA-635P8 amplifiers. Since I need more gain than a single stage can give me, I'm using 3 stages in cascade (although ...
1
vote
1answer
505 views

Pmos or Nmos? Which has the biggest contribution to flicker noise?

I would like to ask if this sentence below is correct.I had find it, when I was reading a paper. "PMOS transistors have lower flicker noise than similarly-sized nMOS transistors in most CMOS ...
4
votes
2answers
83 views

Need help understanding why noise temperatures are added, but real temperatures aren't

Wikipedia says: In a wireless communications receiver, the equivalent input noise temperature \$T_{eq}\$ would equal the sum of two noise temperatures: $$T_{eq} \ = \ T_{ant} \ + \ T_{sys}$$ ...
4
votes
3answers
1k views

Impedance matching vs. voltage gain

So I have an ultrasound system operating in the 1-10MHz range: Pulser -> Tuning circuit -> Transducer -> Tuning circuit -> Voltage amplifier The goal is, I'm trying to optimize the tuning circuits ...
1
vote
1answer
1k views

How to measure Noise Figure of LNA

I know how to calculate Noise figure of an amplifier on the paper but how can measure Noise figure of a LNA in real world? Our lab doesn't have a fancy Noise figure meter but I can readily access to ...
1
vote
2answers
367 views

I am looking for recommendations how to lower the noise in this preamplifier circuit

I have a circuit using MMBT3904T-7-F parts, operating at 100uA collector current, which is rather noisy. This is a preamp for the 475kHz ham band. I need to stick with bipolar NPN. How can I lower ...
11
votes
7answers
916 views

Amplifying a nV signal across a small resistance

I am interested in the feasibility of amplifying/measuring a nV level (or otherwise assumed very small) signal across a small resistance. The SNR of this signal isn't so bad in itself because of the ...
3
votes
3answers
951 views

Why do we care about matching the input impedance of receiving RF amps?

Lets say we have a receiving antenna that intercepts a certain amount of power \$P_r\$ = \$SA_r\$, where \$S\$ is the power flow density of the incoming EM wave, and \$A_r\$ the effective area of the ...
1
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1answer
89 views

Are there any errors in the given Transistorized Microphone Preamplifier With Band Pass Filter circuit below?

Can you spot any corrections or error in the given circuit below: This is the circuit image for "Transistorized Microphone Preamplifier With Band Pass Filter". This circuit is a simple and effective ...
2
votes
1answer
108 views

LDO selection in low noise amplifier application

Assuming a design case where an Ultralow Noise Amplifier like AD8331 is used. This amplifier has an input voltage noise of 0.74 nV/√Hz and input current noise of 2.5 pA/√Hz. The amplified signal will ...
-2
votes
1answer
609 views

50W Audio Amplifier [closed]

How do I make a 50W amplifier using BJT's? We need to use 24V source. For some reason, we weren't able to make it work. without the load resistor (which is supposed to be a 4 ohm speaker), the circuit ...
4
votes
1answer
464 views

Transimpedance-amplifier with 2nd order filter (termination and derivation of transfer function)

I have this schematic from the datasheet of the amp OPA380 (page 12, figure 6c) with a low noise 2nd order filter. I would like to derive the transfer function analytically of this op-amp to get the ...
3
votes
5answers
893 views

When should an audio pre-amp use a differential input

As a guitarist, very familiar with the various types of noise that can wreak havoc with electric guitars, I've been mystified at how infrequently guitar amplifier inputs have employed differential ...
0
votes
1answer
486 views

Automatic Gain Control Circuit Design

I am designing a receive signal path for Ultrasonic Transducer. The circuit needs to measure time of flight of ultrasound wave pulses with frequency of 1MHz(about 16 periods - 16us). Below is the ...
1
vote
1answer
235 views

Advantage of using “IF Amplifier” over traditional OP amp?

I am trying to receive 1MHz ultrasonic signal with transducer. So, I will need to design some kind of filter to only pass 1MHz signal and filter out other noise signals. Searching online for OP amp ...
4
votes
1answer
666 views

Low-noise amplification of microphone signals, tubes or chips?

When trying to capture faint acoustic phenomena, are vacuum tube amplification designs superior to ICs? In this type of application sensitivity and low-noise amplification are the desired objectives. ...
-3
votes
1answer
98 views

How to design a circuit with array of amplifiers? [closed]

If I have a very tiny signal voltage and I want to amplify it 100 times higher with low noise amplifier, how should I design the circuit? I mean for example how should I know that I need capacitors or ...
0
votes
2answers
359 views

How a sensor supply circuit should be? [closed]

i am looking for sensor supply circuit for a sensor. The sensor requires bipolar +-6V to -15V DC and 10 mA power consumption at 6V DC (6V*10mA=0.06mW). Also power supply of this sensor requires less ...
-3
votes
1answer
65 views

Noise when Charger Connected [closed]

I have a handheld rechargeable Measuring Instrument. When I use it normally, without charger connected, readings on screen are stable. But when I connect the charger into it (It's a 5V USB charger) ...
2
votes
1answer
150 views

Cell phone bluetooth range

I've got this phone I'm doing some range testing with...Namely, a Samsung S5 with the latest firmware and I'm testing the WLAN/Bluetooth radio. This phone has unbelievable range...but, when I replace ...
0
votes
1answer
446 views

pseudo differential input of amplifier

The Signal Recovery Model 5184 is an ultra low noise preamplifier. The product description says ... and incorporates a special pseudodifferential input stage that can be floated to give the ...
1
vote
1answer
61 views

S21 parameter of HJFET

I am doing this project on Low noise amplifier using 3503M04 HJFET.My instructor insists I use some resistor in series with the drain to make it more stable.It actually gives a K factor of greater ...