Table of Contents
What is meant by synchronous demodulation?
For synchronous demodulation, a mixer is used. The incoming signal is fed into the signal input of the mixer, and a local oscillator signal on the same frequency as the carrier of the incoming signal is fed into the other.
What is synchronous and asynchronous demodulation?
Synchronous and asynchronous transmissions are two different methods of transmission synchronization. Synchronous transmissions are synchronized by an external clock, while asynchronous transmissions are synchronized by special signals along the transmission medium.
What is synchronous demodulation in context with LVDT?
The synchronous demodulation technique multiplies the LVDT differential output by the excitation signal (or a signal synchronous with the excitation signal in general).
What is the use of synchronous detector?
In electronics, a synchronous detector is a device that recovers information from a modulated signal by mixing the signal with a replica of the un-modulated carrier. This can be locally generated at the receiver using a phase-locked loop or other techniques.
What is asynchronous demodulation?
In Asynchronous demodulators (i.e. self-synchronous), the sum of the two secondary voltages (instead of the oscillator voltage) is generated to control the gates used to rectify the voltage from the secondaries of the LVDT.
What does a demodulator do in an LVDT?
In the context of the LVDT signal conditioning, a demodulator is the circuit that converts the AC output of the LVDT to a DC signal whose amplitude and polarity reveals the core position. Rectification-based demodulators and synchronous demodulators are the two main options that can be used with an LVDT device.
What is meant by synchronous detection of DSB SC signal?
We assume that this locally generated carrier is exactly coherent or synchronized in both frequency and phase with the original carrier wave c(t) used to generate the DSB-SC wave . This method of detection is therefore called as coherent detection or synchronous detection .
What is coherent demodulation used for?
Coherent demodulation in general allows complete compensation for linear impairments in the electrical domain, instead of using optical compensators.
What is phase sensitive demodulator?
As one of the key units in the ac-based capacitance measurement circuit, a phase-sensitive demodulator (PSD) is used to retrieve the amplitude and phase information, aiming to determine accurately the unknown capacitance from the ac signal.
What is working principle of LVDT?
The working principle of LVDT as a displacement transducer is based on mutual induction. When an AC excitation of 5-15 V at a frequency of 50-400Hz is applied to the primary winding, P, a magnetic field is produced. This magnetic field induces a mutual current in the secondary windings, S1 and S2.
How many types of demodulation are there?
Demodulation is the process of decoding the modulated signal into its original form. The three types of modulation are Amplitude, Frequency and Phase modulation.
How to implement a synchronous demodulator using digital circuits?
Rather than using analog building blocks, we can use digital circuits to implement a synchronous demodulator. The basic idea is shown in Figure 7. Figure 7. A digital synchronous demodulator circuit Two A/D converters (ADCs) are used to digitize the input signal (node B in Figure 1) and the sensor excitation sine wave.
How does the ada2200 integrated synchronous demodulator work?
The ADA2200 integrated synchronous demodulator uses a unique charge-sharing technology to perform discrete time-signal processing in the analog domain. Its signal path consists of an input buffer, an FIR decimation filter that performs antialiasing filtering, a programmable IIR filter, a phase-sensitive detector, and a differential output buffer.
What is a square wave-based synchronous demodulator?
Square wave-based synchronous demodulator The two blocks that we’ll examine are the “zero-crossing detector” and the “multiplier.” The “zero-crossing detector” converts the input sine wave into a square wave that drives the switch SW.
What is the function of ADC in digital electronics?
Two A/D converters (ADCs) are used to digitize the input signal (node B in Figure 1) and the sensor excitation sine wave. As shown in the figure, the other blocks are digital and can be implemented by an FPGA.