Are DDS frequency synthesizer and signal generator the same concept?

QWE4562009

Are DDS frequency synthesizer and signal generator the same concept? [Copy link]

Are DDS frequency synthesizer and signal generator the same concept?

Can it be understood that different numbers are formed by coding, and different numbers correspond to different output signals? It is similar to digital-to-analog converters, right? DA conversion! Different codes correspond to different signal amplitudes, phases, and frequencies?

qwqwqw2088

Not a concept.

Signal generators do not necessarily have to be implemented in digital form.

DDS is obviously a purely digital thing

wsmysyn

Obviously, DDS is a more complex DAC. The output stage is definitely still a DAC, but how to output? DDS requires more complex digital circuit control. For ordinary DAC, it is much simpler. Of course, the output stability and accuracy are not that high.

QWE4562009

wsmysyn posted on 2021-11-12 10:04 Obviously, DDS is a more complex DAC, and the output stage is definitely still a DAC, but how to output, DDS requires more complex digital circuit control, for ordinary DAC, ...

Zhou Gong is a master

QWE4562009

wsmysyn posted on 2021-11-12 10:04 Obviously, DDS is a more complex DAC, and the output stage is definitely still a DAC, but how to output, DDS requires more complex digital circuit control, for ordinary DAC, ...

It reminds me of the similarities with the phase-locked loop (PLL).

QWE4562009

wsmysyn posted on 2021-11-12 10:04 Obviously, DDS is a more complex DAC, and the output stage is definitely still a DAC, but how to output, DDS requires more complex digital circuit control, for ordinary DAC, ...

The phase-locked loop usually consists of a phase detector (PD), a filter (LF, loop filter) and a voltage-controlled oscillator (VCO) to form a forward path, and a frequency divider to form a frequency phase feedback path, as shown in Figure 2.

Figure 2 Phase-locked loop schematic

The working principle of the phase-locked loop is to detect the phase difference between the input signal and the output signal, and convert the detected phase difference signal into a voltage signal output through a phase detector. After filtering by a low-pass filter, it forms a control voltage for the voltage-controlled oscillator, controls the frequency of the oscillator output signal, and then feeds back the frequency and phase of the oscillator output signal to the phase detector through a feedback path.

During operation of the phase-locked loop, when the frequency of the output signal proportionally reflects the frequency of the input signal, the output voltage and the input voltage maintain a fixed phase difference, so that the phase of the output voltage and the input voltage is locked.

QWE4562009

wsmysyn posted on 2021-11-12 10:04 Obviously, DDS is a more complex DAC, and the output stage is definitely still a DAC, but how to output, DDS requires more complex digital circuit control, for ordinary DAC, ...

DDS can accurately output frequency with high resolution and good discrimination