| Both sides previous revisionPrevious revisionNext revision | Previous revision |
| university:courses:electronics:electronics_lab_diode_ring_modulator [16 Apr 2019 01:39] – [Question] Hannah Rosete | university:courses:electronics:electronics_lab_diode_ring_modulator [07 Feb 2022 15:11] (current) – [Diode Ring Modulator] Doug Mercer |
|---|
| ====== Diode Ring Modulator ====== | ======Activity: Diode Ring Modulator - ADALM2000====== |
| |
| ===== Objective ===== | ===== Objective ===== |
| <WRAP centeralign> //Figure 5. Diode Ring Modulator Breadboard Circuit// </WRAP> | <WRAP centeralign> //Figure 5. Diode Ring Modulator Breadboard Circuit// </WRAP> |
| |
| Construct the circuitry shown in Figure 5 on a solderless breadboard. Use the 1N914 fast switching diode for the diode ring. Set W1 as a 1kHz sine modulating signal with 1V amplitude and set W2 as a 10kHz sine carrier with a 3V amplitude. For the input and output transformers, a 1:2 turns ratio is needed. You can experiment with other transformer turns ratio and compare output results. For this activity, a Hexa-Path Magnetics transformer with either HP3, HP4, HP5, or HP6 winding layout is needed. If not available, you can proceed with the LTspice simulations. | Construct the circuitry shown in Figure 5 on a solderless breadboard. Use the 1N914 fast switching diode for the diode ring. Set W1 as a 1kHz sine modulating signal with 1V amplitude peak-to-peak and set W2 as a 10kHz sine carrier with a 3V amplitude peak-to-peak. For the input and output transformers, a 1:2 turns ratio is needed. You can experiment with other transformer turns ratio and compare the output results. For this activity, a Hexa-Path Magnetics transformer with either HP3, HP4, HP5, or HP6 winding layout is needed. If not available, you can proceed with the LTspice simulations. |
| |
| ===== Procedure ===== | ===== Procedure ===== |
| |
| ===== Questions ===== | ===== Questions ===== |
| 1. Change the turns ratio of both the input and output transformers. Observe and compare the output waveforms. \\ | 1. Change the turns ratio of both the input and output transformers. Observe and compare the output waveforms. \\ |
| 2. Interchange W1 and W2. Compare it with the original output waveform. What happens to the output waveform?\\ | 2. Interchange the position of W1 and W2 in the circuit. Compare it with the original output waveform. What happens to the output waveform? |
| |
| ====== Simplified Diode Ring Modulator ====== | ====== Simplified Diode Ring Modulator ====== |
| <WRAP centeralign> //Figure 7. Simplified Transformerless Diode Ring Modulator // </WRAP> | <WRAP centeralign> //Figure 7. Simplified Transformerless Diode Ring Modulator // </WRAP> |
| |
| By taking out the transformers, Figure 7 takes a more simplified approach on the traditional diode ring modulator. Both the sum and the difference of the carrier and the modulating signal is fed to opposite junctions of the diode ring by using the ADALM2000 through two low resistance input resistors, R1 and R2, thus taking out the input transformer. The output can be measured across R3 and R4. These resistors then replace the output transformer. | By taking out the transformers, Figure 7 takes a more simplified approach on the traditional diode ring modulator. Both the sum and the difference of the carrier and the modulating signal is fed to opposite junctions of the diode ring by using the ADALM2000 through two low resistance input resistors, R1 and R2, thus taking out the input transformer. The output can be measured across the high resistance output resistors R3 and R4. These resistors then replace the output transformer. |
| |
| ===== Hardware Setup ===== | ===== Hardware Setup ===== |
| |
| ===== Procedure ===== | ===== Procedure ===== |
| | In this activity, we will utilize a carrier with a waveform equation of //f<sub>c</sub> = 3sin(10kt)// and a modulating signal with an equation of // f<sub>m</sub> = 0.5sin(1kt)//. Originally, the two waveforms are multiplied together and the output signal is their product. This contains the upper sideband frequency, f<sub>usf</sub>, and the lower sideband frequency, f<sub>lsf</sub>. Their definitions being: \\ \\ |
| | |
| | <WRAP centeralign><m>f_usf =f_c + f_m</m></WRAP> |
| | <WRAP centeralign><m>f_lsf =f_c - f_m</m></WRAP> |
| | |
| | where: |
| | * f<sub>c</sub> = carrier signal |
| | * f<sub>m</sub> = modulating signal \\ |
| | |
| | In this simplified approach, we will directly feed the sidebands to the inputs. Taking note of the carrier and the modulating signals, we will have //f(t) = 3sin(10kt) + 0.5sin(1kt)// for the upper sideband and //f(t) = 3sin(10kt) - 0.5sin(1kt)// for the lower sideband. |
| |
| In the signal generator, set the equation //f(t) = (3*sin(10*t)) + (0.5*sin(t))// with a 1 kHz frequency for W1 (Ch1), and //f(t) = (3*sin(10*t)) - (0.5*sin(t))// with the same 1 kHz frequency for W2. In the oscilloscope, set the horizontal at 200 us/div and the vertical at 500 mV/div. Run the signal generator and the oscilloscope and observe the waveform. It should have a similar result with the waveform below. | In the signal generator, set the equation //f(t) = (3*sin(10*t)) + (0.5*sin(t))// with a 1 kHz frequency for W1 (Ch1), and //f(t) = (3*sin(10*t)) - (0.5*sin(t))// with the same 1 kHz frequency for W2. In the oscilloscope, set the horizontal at 200 us/div and the vertical at 500 mV/div. Run the signal generator and the oscilloscope and observe the waveform. It should have a similar result with the waveform below. |
| <WRAP round download> | <WRAP round download> |
| **Lab Resources:** | **Lab Resources:** |
| * Fritzing files: | * Fritzing files: [[downgit>education_tools/tree/master/m2k/fritzing/diode_ring_mod_bb|diode_ring_mod_bb]] |
| * LTspice files: | * LTspice files: [[downgit>education_tools/tree/master/m2k/ltspice/diode_ring_mod_ltspice|diode_ring_mod_ltspice]] |
| </WRAP> | </WRAP> |
| |
| |
| Some additional resources: | Some additional resources: |
| * [[https://www.analog.com/media/en/training-seminars/design-handbooks/Basic-Linear-Design/Chapter4.pdf |RF/IF Circuits]] | * [[adi>media/en/training-seminars/design-handbooks/Basic-Linear-Design/Chapter4.pdf |RF/IF Circuits]] |
| * [[http://recherche.ircam.fr/pub/dafx11/Papers/66_e.pdf|A Simple Digital Model of the Diode-Based Ring-Modulator]]. Parker, J. Aalto University, Finland | * [[http://recherche.ircam.fr/pub/dafx11/Papers/66_e.pdf|A Simple Digital Model of the Diode-Based Ring-Modulator]]. Parker, J. Aalto University, Finland |
| * [[https://www.tutorialspoint.com/analog_communication/analog_communication_dsbsc_modulators.htm |Analog Communication – DSBSC Modulators]] | * [[https://www.tutorialspoint.com/analog_communication/analog_communication_dsbsc_modulators.htm |Analog Communication – DSBSC Modulators]] |
