Hi Dean, Referring to to Figure 37 on the same page, the modulator output mode bypasses all of the internal digital filtering of the ADS1282 . Instead of getting a single settled conversion result, you will get a digital bit-stream and will have to compute the value given by equation 5. From there it would be up to you to implement a digital filter in your MCU with your required filter specifications. NOTE: When the ADS1282 is in modulator mode, the data rate register setting will have no effect on the output MOD clock (or data rate), as this only configures the SINC filter's decimation ratio. As far as data rates go, the SINC filter mode will provide you with the fastest data rates, and enabling the FIR filter will reduce the output data rate (decimated by 32). The group delay of the SINC5 filter is flat, but the group delay will increase as you decrease the data rate. Enabling the FIR filter, you have the choice between minimum phase and linear phase. The minimum phase filter has a much lower group delay; however, this delay is frequency dependent. [quote user="Dean Gacita"]Again looking at page 18 Table 6 of the datasheet I see if I select DR at 100 I get a data rate of 128K = 7us phase delay. Bypassing the programmable digital filter - is it correct for me to assume that would be my total group delay? [/quote] I'm not quite sure what you mean. At the 128kSPS data rate the time between continuous conversions will be 7us; however, the first settled filter result will require ~63 conversion or 63*7us = 441us. This is assuming you are in SINC filter mode. By bypassing the digital filter you will get data out at the MOD clock frequency, but to use this data you will need to perform the weighted moving average, given by equation 5. Please NOTE: At the 128kSPS data rate the SCLK is not fast enough to clock out 32-bits of data, so you'd have to truncate the data. References: https://e2e.ti.com/blogs_/archives/b/precisionhub/archive/2015/01/21/delta-sigma-adc-basics-understanding-the-delta-sigma-modulator https://e2e.ti.com/blogs_/archives/b/precisionhub/archive/2015/02/10/delta-sigma-adc-basics-how-the-digital-filter-works Did I answer your question?
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Forum Post: RE: ADS1282: ADS1282
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Forum Post: RE: DAC161P997: DAC161P997 Breaks down without reason
Hello, This may be causing a some type of transient that is damaging the device. The device is not damaged if the output is not switched while the device is on, correct? I would monitor the voltage on VA, VD, BASE, and OUT while this switching occurs to see if you can identify the issue. Thanks, Garrett
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Forum Post: ADS1282: Need to know what the -1 identifies on the part.
Part Number: ADS1282 Please advise what the -1 identifies on this device. Date codes 2008 and 2011. Rochester received stock from TI in 2010 & 2016. Packing lists from parts received show -1. Is this something internal to Texas Instruments as it is not identified on the data sheet. Please advise. Thank you, Vicki TI part number ADS1282IPW-1
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Forum Post: RE: ADS1148: unable to clock out conversion result
Hi Jessica, Thanks for your post! Can you please post the pictures and code here on the forum? I cannot access dropbox on the network.
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Forum Post: RE: TSW14DL3200EVM: Also Unable to Power on Board
Hi Kirk and David Have you managed to make any progress with this issue? Please provide an update. Best regards, Jim B
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Forum Post: RE: ADC12DJ2700EVM: Compatibility with ZC706
Thanks Hajun My colleagues are working to get the adapter shipped to you. I will send you shipment information once I have it. Best regards, Jim B
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Forum Post: RE: TPL0102-100: Write protect
Hello Duke, Thank you for your reply. The customer are worried about whether the data written to the EEPROM will not change due to noise or some else. There seem to be a little possibility, because the wiper positions are accessible. Thanks, Naoki Aoyama
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Forum Post: RE: TSW14DL3200EVM: Also Unable to Power on Board
Hi Jim, Yes, I've been able to get the board powered by touching the gate of Q10 with a scope probe. The input protection is very sensitive. It keeps cycling off until I put a load on the gate. Looking at the datasheet for LTC4365 (U11) they recommend to use a TVS rather than the diode that's on the board. Kirk
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Forum Post: RE: AFE5809: Questions about AFE5809 CLOCKs
Hi Yi, 2, Jitter always is in "Time" domain. I looked through your attachment, which also use RMS jitter. So TI "Additive Jitter RMS" = ADI "Additive (RMS) Time Jitter", TI "RMS jitter" = ADI"Absolute (RMS)Time Jitter". 3, "For PCB layout and routing of 16pcs of AFE5809 , we generally reuqire ADC clocks' traces to be equal-length with very small tolerance, and make it more difficult for routing. How should we select the proper length tolerance? ADC sample freq. is 50MHZ." Sampling period = 1/50 MHz = 20 ns Suppose PCB FR4 Er =4.5, inner trace propagation delay is around 180 ps/inch. It is correct to keep ADC clocks' traces to be equal-length. The trace length difference tolerance depends on your sampling system synchronization accuracy requirements. Best Regards, Shawn
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Forum Post: RE: ADS8900B: What is the use of pattern registers?
Hi Keith... So, if the DATA_VAL=0 then the output is directly streaming from output data register of ADC, if DATA_VAL=1 then the output is from pattern registers with customised pattern. In high speed sensing, whether the pattern registers are continuously writing by ODR? Or this is particular value only?? Can you please help me to understand with a small example? Thanks,
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Forum Post: ADS1292R: Plz, help me.
art Number: ADS1292R I'm not used to Eng. I can read test signal well. *Sampling rate 250Hz y-axis is mV, x-axis is sample number. But I can't read correct signal from electrodes that were connected with CH1. and the signal was 3Hz-50mVpp-Sine wave from function generator. *Sampling rate 500Hz. y-axis is mV, x-axis is sample number. It is similar 3Hz(three periodic wave in 500 samples, 1 sec) but with only positive polarity. and also the amplitude is not correct. So I changed polarity of input cable. then, ... I want to read whole sine wave. why these error occurs? my schematic is VREF was well measured at 2.42V and register set write_reg(0x01, 0b10000010); write_reg(0x02, 0b10100000); write_reg(0x03, 0b00010000); write_reg(0x04, 0b00000000); write_reg(0x05, 0b10000000); write_reg(0x06, 0b00000000); write_reg(0x07, 0b00000000); write_reg(0x08, 0b00000000); write_reg(0x09, 0b00000000); write_reg(0x0A, 0b00000011); write_reg(0x0B, 0b00000000); plz, help me.
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Forum Post: RE: ADS1282: Need to know what the -1 identifies on the part.
Hi Vicki, We are looking into this for you, we should have an answer to you by COB tomorrow (12DEC19).
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Forum Post: RE: ADS1292R: Plz, help me.
Hi Seonjo, I suspect you do not have any DCbias (offset) setup on the signal generator you are using with the ADS1292 . With the single ended supply you have (AVSS tied to GND, AVDD at +3.3) the input signal has to remain above 0V. Try adding some positive offset to your input signal and see if that corrects the problem.
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Forum Post: RE: AFE4300: inconsistencies in bcm adc
Hi Abhinav, When you power up the signal chain, the internal nodes of the device can be different each day. This will affect the channel offset as well as excitation current. So its better to do calibration every time you power up the device. Regards, Prabin
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Forum Post: RE: DAC5681Z: As a high speed driver
Hi Neeraj, Thank You for your answer! The material was very effective for me. Is it difficult to output a staircase light pulse? Please give me a point of view about this. Best Regards,
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Forum Post: RE: ADS1292R: Plz, help me.
Can you recommend/draw me how to connect correctly INN for measuring ECG/EMG?
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Forum Post: AFE4300: Connections For BCM
Part Number: AFE4300 I am using afe4300 with stm for BCM computation. I have noted adc values of known resistances at 50khz and made a piecewise linear curve and getting relevant data for resistances. For doing this i have used the application circuit on page 30 section 8.1.1 of the afe 4300 datasheet. I have a doubt regarding the connections to be made when using this for the measurment of human body impedance. Can i please get assistance for this? Thanks and Regards Abhinav Nagaraj
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Forum Post: RE: ADS1246: ADS1246 with 3.3V AVDD
Thanks for the feedback, Alexander! Looks like I will have to rethink my setup a bit and look at the others. Thank you for the recommendations. Leo
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Forum Post: ADS1298R: Pacing pulse inhibition and test signal problem
Part Number: ADS1298R hi， I am using ADS1298R for ECG detecting. It works fine, but we have encountered some problems while adding some applications. Mostly two questions here: 1\ I have known ADS1298R can detect pacing pulse with sofeware or hardware. But my question is that is it necessary to add pacing pulse inhibition circuit while using ADS1298R to a person who have heart pacemaker？ Will the internal ADC be saturated in this situation？If I need to add pacing pulse inhibition circuit，how？ 2\ We are setting the internal test signal as following fig (Page85 of datasheet). As the following process shows the test singal should be +-1mV*Vref/2.4, but we found that the output data of ADS1298R is +4.3mV/-7.6mV(simply says we set test signal use registers and get the data from ADS1298R , no external input or output). Our settings are: PGA_Gain is 6, TESTP_PACE_OUT1 and TESTN_PACE_OUT2 are not used (Testp is connected to a test point, testn is unconnected). Could you help explain this? why this test signal is not +-1mV? and why there is a unknown offset? Hopefully for your replay, thank you.
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Forum Post: RE: LM98725: Question about sampling mode
Hello, Maybe the ratio between active white pixels and edge pixel ( on each side of the active ones ) is not the same as the previous sensor. You can enable the dual gain settings and have different gain for the active and the side pixels, increasing the side pixel gain may help. Another possible sensors difference may be the even/odd pixels. It is possible new sensor needs different odd/even offset coefficients, this functions can be enabled. Regards, Costin
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