Type 4250
Phase-Locked Loop (PLL) Type 4250
Type 4250 is a training platform for frequency and phase control. The functions are split into individual modules and can be tested with little measuring equipment. This makes the board suitable for an introduction to PLL and synthesizer technology.
- PLL trainer for frequency and phase control
- Low measurement effort required
- Functional modules can be checked separately via test sockets
- Generators, dividers and phase shifters integrated
- Suitable for AM, FM, PM and FSK experiments
- Detailed experiment descriptions in the manual
Functional structure
The board presents the main building blocks of a PLL in a clear way. Reference generator, VCO, dividers, phase detectors and loop filters are arranged so that their effect in the closed loop can be followed directly.
Separating the functional groups makes measurements on the individual stages and on the complete PLL easier.
Typical applications
The system can be used to study modulation and demodulation methods as well as the structure of a frequency synthesizer. It also includes stereo and PAL decoders, phase shifters and several VCO operating modes.
The didactic focus is on hold range, capture range, loop behaviour and divider structure.
- Square-wave generator
- quartz-stabilised; 1 Hz, 1 kHz, 2 kHz, 4 kHz
- DC source
- 1 V to 5 V
- VCO input
- 0 ... +5 V
- VCO output
- +5 V symmetrical square wave
- VCO frequency range
- approx. 20 Hz ... 6 kHz
- Phase detector
- Type I with XOR; Type II with JK flip-flops and charge pump
- Loop filter
- Type I RC low-pass 300 Hz; Type II R/RC low-pass 3 Hz
- Frequency dividers
- N1 and N2 from 1 to 10
- Phase shifter
- -7° ... -230° or +7° ... +230°
- Supply
- +5 V DC; approx. 150 mA; via external power supply
- Dimensions
- 266 x 297 x 110 mm
- Weight
- 1.3 kg
- Recommended accessories
- Experiment manual V 0068 and power supply
- Measure the characteristics of both VCOs
- Study the phase shifter
- Analyse phase detector type I
- Analyse phase detector type II
- Measure low-pass and loop filters
- Evaluate the closed control loop
- Determine hold and capture ranges
- Find the possible divider values of the synthesizer
- Measure the dynamic behaviour of the PLL
