hey all,
I would like your opinion on something. As from the data sheet of the adc chip, ad7819 it states that the Vin is between the range of 0V to Vref. After doing throught the adc ann then dac, a full sine wave is observed. But if the Vin is has a range from 0V to Vref i thought after the DAC i would only be able to see the positive half cycle.
hey all,
I would like your opinion on something. As from the data sheet of the adc chip, ad7819 it states that the Vin is between the range of 0V to Vref. After doing throught the adc ann then dac, a full sine wave is observed. But if the Vin is has a range from 0V to Vref i thought after the DAC i would only be able to see the positive half cycle.
im sorry. but can i know what is opa? do u mean opamp? so even though the Vin is from a range of 0 to Vref i can still observe the full sine wave as long as the offset is set to Vref/2? but i dont have a offset pin on my dac
im sorry. but can i know what is opa? do u mean opamp? so even though the Vin is from a range of 0 to Vref i can still observe the full sine wave as long as the offset is set to Vref/2? but i dont have a offset pin on my dac
ok got it! but the thing now is i did not use an op-amp to the input of my ADC. The input into my ADC is a sinewave directly from the function generator and the 8-bit binary output is directly into the DAC. Hence, im curious while im seeing a full sine wave
ok got it! but the thing now is i did not use an op-amp to the input of my ADC. The input into my ADC is a sinewave directly from the function generator and the 8-bit binary output is directly into the DAC. Hence, im curious while im seeing a full sine wave
The output from the FG has been observed using the oscilloscope and i've adjust the amplitude of the sinewave to say 2.5Vpp. After going through the A2D and going throught the D2A again, the reconstructed sinewave is observed to have almost the same amplitude (2.5Vpp) as the input signal. A full sine wave can be observed. hmm
The output from the FG has been observed using the oscilloscope and i've adjust the amplitude of the sinewave to say 2.5Vpp. After going through the A2D and going throught the D2A again, the reconstructed sinewave is observed to have almost the same amplitude (2.5Vpp) as the input signal. A full sine wave can be observed. hmm
Yes. This graph is obtained when i observed the output using LEDs. The input however is a dc voltage. When i use a AC voltage instead, the LED is observed to be blinking and increasing from 00h to FFh. However when i use a DAC to check the reconstructed signal, i assume i shouldnt see a full sine wave as a level shifter is not use yet. yes. The frequency and the Amplitude of the input signal are almost similar to that of the signal from the DAC. Strange huh?
Looking at the AD7819 datasheet, shows two clamp diodes on the Vsig input, the lower lower clamp diode [~0.7] should clip any below zero input voltages.!
EDIT:
Just because the LED's are showing a full sweep when using an 'ac' input dosnt mean its a sinewave output.
Its most likely a half cycle swing, due to the clamp diode' you are seeing on the LED's
I thought you were using a scope, showing a true sinewave.!!
Looking at the AD7819 datasheet, shows two clamp diodes on the Vsig input, the lower lower clamp diode [~0.7] should clip any below zero input voltages.!
it is possible not possible to observe the output sinewave directly from the ADC as it is an 8-bit binary. Thats why im using a DAC to check the reconstructed signal to confirm the input signal
it is possible not possible to observe the output sinewave directly from the ADC as it is an 8-bit binary. Thats why im using a DAC to check the reconstructed signal to confirm the input signal
Im convinced that the output of the A2D is not a true sinewave, when you are driving the input from sinewave thats swinging about zero, ie +/-V over the full input range.
Im convinced that the output of the A2D is not a true sinewave, when you are driving the input from sinewave thats swinging about zero, ie +/-V over the full input range.