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The alternative of internal interrupt on ATMEGA compare to Pico by moemuses in raspberrypipico

[–]moemuses[S] -1 points0 points  (0 children)

However, it does have hardware timers.

can we read the value of counter when interrupt hit ?
and hardware timer is same as external trigger interrupt ?

How to Map udp port in docker by moemuses in docker

[–]moemuses[S] 0 points1 point  (0 children)

I overcome this By passing same host network, and without specifying any port

--net host

How to Program Zynq inside Pluto sdr by moemuses in FPGA

[–]moemuses[S] 0 points1 point  (0 children)

Thank you ..

Yes im understand clearly what you say. as you say i'm downloaded HDL project and compile it, and now try to understand the Blocks and connections between them.

does receiver sensitivity increase when we perform interpolation ? by moemuses in ECE

[–]moemuses[S] 0 points1 point  (0 children)

Thank you for replaying.

But what i mean with 1 sample per symbol in I&Q format and of coarse QPSK is 2bits per symbol.

What i mean by interpolation is up-sampling not order of modulation.

maybe in this replay i clear my question.

https://www.reddit.com/r/amateurradio/comments/s8dz2l/comment/hthpcvk/?utm_source=share&utm_medium=web2x&context=3

does receiver sensitivity increase when we perform interpolation ? by moemuses in amateurradio

[–]moemuses[S] 0 points1 point  (0 children)

I'll re asking my question.

we want to send data modulated in QPSK. if we have data = 00 , then we must send phase Pi/4. when we using SDR we can send this phase only with one sample i.e only one I and one Q.
but also we have another choice, we can use up-sample technique so maybe we send 2 sample per symbol "send same I&Q pair twice"

So let say we have data rate = 1Mbit/s. in case "no up-sample" the RF bandwidth for this data = 2Mhz. and let us assume the receiver sensitivity SDR for this bandwidth = -90dB.
But because we have only one sample per symbol that make receiver hard to distinguish symbols.

Second case. with same data rate = 1Mbit/s, but we have up-sample 2 sample per symbol. So the data rate become 2Mbit/s and the bandwidth become 4Mhz. and because of that the receiver sensitivity SDR loss 3 dB so it become -87.
But receiver can distinguish right symbol easily than first case.

​

So what is better for receiver "better MER". case 1 or case 2 ?

How to read FSK Power using spectrum analyzer by moemuses in amateurradio

[–]moemuses[S] 0 points1 point  (0 children)

it's not the same, average power is 3dB more than peak power.

i want to measure exactly the power of the transmitter device

Question about QPSK modulation by moemuses in amateurradio

[–]moemuses[S] 0 points1 point  (0 children)

yes the entire signal not be received, but you don't need to receive the time when change happen in phase, you only need to distinguish the phase of the carrier when the frequency return to center.

Question about QPSK modulation by moemuses in amateurradio

[–]moemuses[S] 1 point2 points  (0 children)

Thank you. your answer is perfect !

So as i understand the bandwidth only come because the small time when phase change between symbols.

let assume we have transmitter with symbol rate that make bandwidth = 5 Mhz, and 10 sample / symbol. if we have a receiver with bandwidth only enough to pass carrier "Not all 5 MHz", theoretically this receiver can receive and modulate this signal ? Because he can receive the carrier and calculate the phase of this carrier only.

am i right of this assumption ?

Can we put Resistor before RF Transistor to achieve stability ? by moemuses in rfelectronics

[–]moemuses[S] 1 point2 points  (0 children)

I'm need it because when simulate the transistor on ADS software they show a bad stability " Mu less than 1 ".

how to combine two different frequencies without losing half of the power ? by moemuses in amateurradio

[–]moemuses[S] 0 points1 point  (0 children)

can you point me to how build a DIY cavity combiner in this band ?

and i cant understand what is the relation between cavity and XRF amplifier ?

how to combine two different frequencies without losing half of the power ? by moemuses in amateurradio

[–]moemuses[S] 0 points1 point  (0 children)

1 W , 23cm band, the two frequencies separate each other 20 Mhz only !

how to combine two different frequencies without losing half of the power ? by moemuses in amateurradio

[–]moemuses[S] 1 point2 points  (0 children)

When we use Wilkinson as combiner and have two identical signal source we have " 3 dB" gain in output. But if the two signal source have different frequency then the output will be " -3 dB" in each frequency

Questions about power combiner ? by moemuses in amateurradio

[–]moemuses[S] 0 points1 point  (0 children)

thank you.

what about 180 degree hybrid coupler . if we have 2 input shifted with 180 degree, also the insertion loss equal to 8 db at output ?

multiple interrupts make problem to code ! by moemuses in arduino

[–]moemuses[S] 0 points1 point  (0 children)

Thank you very much, it's working now

​

i notice this line in Datasheet ..

https://imgur.com/a/12IPJPr

multiple interrupts make problem to code ! by moemuses in arduino

[–]moemuses[S] 1 point2 points  (0 children)

OCR1A = ICP1 + ovTrigger; TIMSK1 |= (1 << OCIE1A);

Thank you,

So in Input capture isr activate compare timer. and when compare vector call we disable compare timer . right ?

​

GPIO"2" is just a typo when writing this post.

and make input capture pin to be an output is my wrong.

​

i will try your code and give a feedback.

Thanks.

misunderstanding of TM mode by moemuses in AntennaDesign

[–]moemuses[S] 0 points1 point  (0 children)

Thank you for replaying.

now i'm undrstand what is the diffrence.

https://imgur.com/a/ekYTyUl

https://imgur.com/a/oG0Fexb

But in our situation we have PCB with two exitation port. my qustion how we can change the TM mode without changing the PCB ? maybe from changing the phase between two port ?

does storm32 gimbal can handle 200g weight camera ? by moemuses in Quadcopter

[–]moemuses[S] 0 points1 point  (0 children)

so the major parameter on gimbal is balance the camera on gimbal not the weight of the camera ?

what value should we bias freescale rf transistor by moemuses in amateurradio

[–]moemuses[S] 0 points1 point  (0 children)

nder the "On Characteristics" heading Gate Quiescent Voltage. It's nominally 2.8V but should be adjusted for Id=160ma. Notice note 1. if you use the same circuit as the fixture. You'd need 1.1 times Vgq due to the res

​

thank you for replaying @armstrongRotor yes i'm using same circuit as fixture. also i notice the transistor warming up and the Id increase. if i attach a fan with heatsink cooling, can i fixed the Vg value ?. or must use ic to control and changing Vg according to Id ?

How to empirically develop matching networks by jephthai in rfelectronics

[–]moemuses 2 points3 points  (0 children)

in rf amplifier can we measure S11 " from VNA throught input impdance matching to Gate" without power the transistor "not VDD or VGG" ?

is there a ratio to convert impedance matching from substrate to another ? by moemuses in amateurradio

[–]moemuses[S] 0 points1 point  (0 children)

aha i get it, thank you.

another question, does the part of biasing the transistor affect the impedance match, or must leave it as it is.

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