# Questions tagged [dsp]

DSP stands for Digital Signal Processing or Digital Signal Processor.

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### FIR Lattice Filters

In DSP, sometimes the so-called Lattice Filters are use, having a structure like on this picture: I wonder what the advantages of the Lattice structure are, compared to other FIR filter types and ...
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### How to Switch DSP to Passive Speaker Driver?

I am working on an Active Noise Reduction project for a headset using Codec ADAU1772 from AD. There are two inputs, one of which is feedback mic. connected to AIN0, second is INT+ (Intercom or music) ...
76 views

### Why does a cosine function have a non-infinite Fourier coefficient?

I took my signals class a long time ago and have gotten used to using Fourier tables for a lot of things. I'm reading a textbook on communications and I stared at the Fourier transform equation for a ...
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### Adding Line Out / Sub Out to LG soundbar

I have LG Soundbar with wireless sub. I am trying to add Line output, so i could connect a wired sub. I took some pictures of the boards and chips. If someone could point me in right direction on ...
250 views

### How to amplify the output of a digital low pass filter?

I have used the transfer function of a RC low pass filter to design a IIR Digital low pass filter. $$H(s)= \frac{1}{sRC+1} ;First \space order$$ H(s)= \...
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### RC filter - compute output as a function of input for generating waveform

I'm not so deeply into the theory about all this, I may use strange terminology... If I put a square wave through a simple lowpass RC filter, the output will be a sort of "rounded sawtooth", well not ...
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1 vote
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### Understanding how a digital microphone's output gets stored in DSP memory

I am working with a DSP that takes audio input from a digital microphone. For the sake of this discussion all input sounds are pure sinewaves. The DSP receives microphone data as 24-bit numbers. Let's ...
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1 vote
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### How would I draw a signal flow diagram for the transfer function of a resonant filter?

The transfer function is: $$H(z)=\frac{(1-r)(1-rz^{-2})}{1-2r\cos(\omega T)z^{-1} + r^2z^{-2}}$$ I have started by finding the difference equation, but I don't know how to draw a signal flow diagram ...
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1 vote
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### Tuning controllers in dual-loop control with feed-forward and decoupling signals

What would be the best step-by-step approach to tune PI controllers in a dual-loop control with decoupling and feed-forward signals? I am trying to tune both the voltage and current controller in DSP ...
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1 vote
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### Relative error of power estimation

I'm reading my teacher code for FFT windowing in Matlab and there is one thing I don't understand. When you run the code at the end it says: ...
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1 vote
71 views

### Best way to output n digital signals using n-1 DAC channels

I have 3 digital signals that need to be mixed and output into the analog domain. My DAC has 2 channels (Left and Right). The way I see it, I can: mix the signals 1, 2, and 3 digitally and output ...
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1 vote
56 views

### How to measure the time it takes to receive a new sample from CODEC using a fixed sample rate of 48kHz?

in my current set up I have a CODEC set as master connected to my STM32F446RE (slave). The current configuration utilizes I2S DMA interrupt callbacks to handle the input and processing of these ...
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### Discrete time decimation bandwidth expansion

I have been reading about discrete time decimation in Signal and Systems by A.Oppenheim. The decimation process expands/scales the bandwidth of the original non-decimated signal by N, I have a hard ...
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1 vote
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### Lattice FPGA: Mach X02 7000 Can it be used for DSP?

I have a MachX02 7000 having 6800 LUT's. I want to implement DSP algorithm involving floating-point DSP algorithm on 2 14 bit ADC input data. Is it possible to perform on this FPGA with low LUT's, No ...
1 vote
254 views

### How does stretch processing work for SFCW?

I've been reading about FMCW radar, and I understand that a chirped signal can be de-chirped by mixing it with a copy of itself, which yields a beat frequency which is much easier to process and is ...
1 vote
88 views

### Converting Clipping stage of guitar pedal to a formula for use in DSP

Been trying to figure out the clipping stage of a tube screamer so i can implement it in a DSP project. I can simulate a clipping effect by using a tanh(input) type function, which gives me an OK ...
1 vote
66 views

### Help with Project

[Difference Eqution]: $$LPF_D=\frac{0.1441z^2+0.2881z+0.1441}{z^2-0.6777z+0.254}$$ With a sample of $T_s =$ 8e-6 seconds, in scientific E notation. The difference equation: $Y$ = Output $U$ ...
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1 vote
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### STM32F4 DSP noise with inbuilt ADC and DAC

I'm trying to perform signal filtering with STM32F407VGT. I've set up the ADC and DAC to work synchronously, triggered by a timer at 42kHz, and using DMA. The idea is to process half of the buffer ...
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1 vote
759 views

### Wrong FFT result when using rfft function on STM32F4

I'm trying to use rfft function in STM32F407G and I am getting wrong results when I compare it with an online fft calculator . I give a sample input as {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,...
1 vote
99 views

### Non equal phase currents at nominal speed vector control Permanent magnet synchronous motor

I working on my implementation of vector control for PMSM. I'm having close loops over speed, current in d axis(flux loop), current in q axis(torque loop). I'm using MATLAB/Simulink for vector control ...
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1 vote
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### dsPIC33EP512GP502 -> ADPCM?

It seems that ADPCM is all but non-existant anymore. But I'd like to use this to compress six high-quality audio channels into a smaller bit-stream with little overhead. There seems to be a dsPIC G....
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1 vote
158 views

### RMS calculation of signal with high crest factor up to 10 MHz

I'm attempting to measure the RMS of an AC signal with a crest factor of up to 10, at frequencies of up to 10 MHz. From my brief research I can see many ICs that work well above 100 MHz (designed for ...
45 views

### Phase noise compensation in carrier tracking loops at 38 GHz

I am trying to reach an estimate for a number in dBs of phase noise improvement in a Costas tracking loop. I know that there is a trade off there as increasing the loop BW helps reducing the input ...
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### DAC and ADC Clipping, Headroom before Clipping, Peak and RMS confusion

If I wanted to calculate the back off or headroom of a signal before clipping in an ADC, should this be the difference between the ADC peak full scale and the RMS of my signal or should it be the ...
• 369
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### What's the maximum sample rate for lattice wave filter?

From Wanhammar, Lars DSP Integrated Circuits: EXAMPLE 6.5 The filter shown in Figure 6.30 has been implemented using so-called redundant, bit-parallel arithmetic in which long carry propagations are ...
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### Problem with I2S and IIR-filter

I am working on a system that receives audio data over Bluetooth using a BM83. This is transmitted to an STM32F7 over ADC, an IIR-filter is applied and the data is transmitted out over I2S. The ADC ...
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### DSP VS FPGA for Power electronics Solar inverters

I need some help regarding the use of an FPGA or DSP for the control loop of the three-phase solar inverter. I want to implement a digital feedback system (as shown below) instead of analog and ...
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### EPWM1 and EPWM2 are not in sync TMS320F28379D

I am using LAUNCHXL-F2379D, I am creating sine wave of 50Hz using math function. positive half of that sinewave I am giving it to EPWM2 (working on 10kHz) whereas during negative half of the sine wave ...
56 views

### Understanding the nature and the impact of gain flatness on EVM of a transmit signal

I have a signal which has a quite a steep slope in frequency domain (or gain non-flatness), in fact 3 dB. This signal will go through an amplifier and it is going to be operated in the saturation ...
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### Understanding reflection calculation in Wave Digital Filters

I'm trying to grasp this implementation. It involves calculating the reflected wave (b1) using the reflection coefficient and the incident plus reflected waves at two ports in a series adaptor. The ...
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### What to choose for an RF spectrum analyzer A/D conversion

I assigned myself a (long term) project to build an RF spectrum analyzer. In the basis it will be a super or triple (depending on frequency band) heterodyne frontend with digitized IF and some final ...
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### Gain of a signal passed through a N element phased array?

Assuming a isotropic phased array of N elements, the gain would be 10*log10(N) dB which is provided in theory. However, when same signal is passed through all the N elements, the gain is 20 * log10(N) ...
38 views

### How to find unit-sample response

I have found: $$Y = (X + Y)R^3$$ then $$\frac{Y}{X} = \frac{R^3}{1-R^3}$$ then $$\frac{Y}{X} = \frac{1}{(z-1)(z-e^{j2\pi/3})(z-e^{-j2\pi/3})}$$ then I have three poles: $$1, e^{j2\pi/3}, e^{-j2\pi/3}$$...
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### FPGA Ressource Estimation

Currently I'm planning my 'first' FPGA project. I did some VHDL during university, but have no 'practical' experience yet. Therefore, I'm having a hard time estimating the resources required before ...
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### Eliminating noise from ADC readings using digital filters

I need to take some measurements using MCU internal ADC from the following circuit, to be able to calculate the amount of current produced from the programmable current source which discharging the C2 ...
96 views

### Magnitude of transfer function

I was able to find the transfer function of this LTI system block diagram, but am unsure of where to start on how to find the magnitude. The transfer function I have from this is: H(s) = \frac{Y(s)}{...
55 views

### Why is the filter output not in sin form?

The lowpass filters I created with the Matlab fda tool are different from the sinus form in the simulation. What could be the reason for this?
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### How is noise analysis done in practice

If we identify a signal as a Random Process how do we study it in practice, how to determine its characteristics such as stationarity(whether it is Stationary, Wide Sense Stationary or ergodic),how to ...
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### How to classify filters

I deal with digital signal processing which also deals with filters. There are 2 main types of filters: Analog and Digital. To each type there are several classifications such as:FIR/IIR/RCSR(...
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### Converting an analog controller into a digital controller... Theory

I have created a stable PI s domain controller for my system. When I go to digitize it in PSIM by adding a ZOH and a delay block and by converting the PI controller into the z domain using backward ...
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### Need help with timing in Verilog functions

I'm doing a filtering project and I'm writing a module that feeds a lot of data to some compute units. There's a lot of really repetitive code and I was wondering if there was any way to condense it, ...
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### The effects of frequency resolution in FFT on the frequency spectrum

This is a section for the parameter study of my thesis (basically: why and how I did what I did in the experiments). Currently, I have to choose the fit bandwidth and FFT lines combination for the ...
394 views

### FPGA multiplication using DSP hardware, signed vs. unsigned

I'm using the DSP unit (just a fancy name for the multiplier/accumulator unit) of the Gowin GW1N devices to do some fairly simple math. These units accept two 18 bit inputs for the multiplier adding ...
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### How do I find the coefficients to know if this color combination is realizable? What am I doing wrong in my solution?

I tried to solve the following problem: Part A was solved without any problem, however with part B there is a problem: Second the digital signal processing, to be more specific, image processing, I ...
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### External SDRAM with Blackfin and FreeRTOS

I have a custom board with Blackfin DSP and External SDRAM 64 MB and FreeRTOS. Reading from SDRAM using task with priority 6. In a test I read about 20000 words. Each word is twice consecutively, some ...
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### WCDMA , 8PSK signal, 3 G , user end sensitivity, required SNR

Does anyone know how the User End receiver sensitivity for a 3G WCDMA, 8 PSK signal is calculated? and what is the typical SNR required to detect the signal?
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### LTE, downlink multiple antenna channel estimation with and without Channel State Information (CSI)

In an LTE downlink with CSI at the transmitter, is the radio Tx in the base station and Rx at the user end hardware part of the channel estimation? example: Tx to Tx and Rx to Rx isolation between ...
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### Double Sideband Suppressed Carrier modulator List

I am using ring modulator for DSB-SC am modulation in a transmitter circuit. Can anyone please tell me about more DSB SC modulator for am modulation? I want to know which one to use where?
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### Filtering Options for an RTL-SDR (DSP and Analog routes)

I have several related questions regarding filtering for an RTL-SDR radio. It's readily swamped by the very, very strong AM and FM radio stations local to me. So much so that your basic passive RC ...
196 views

### How to synchronize TI high precision ADC and DAC via SPI?

I am working with DAC80504EVM and ADS8920BEVM-PKD from TI. I am trying to design a system which uses TMDSEVM6657EVM processor board to communicate with these converters via SPI. However, I am trying ...
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