Education electronic circuit training kits / High frequency modulation / demodulation trainer


Product description

The whole system consists of one main control module and five basic experimental modules, which can complete more than 20 practical training including high-frequency electronic each unit circuit experiment, wireless transceiver system debugging, fault setting determination, and experimental evaluation. 

Product Detail

Product compositions

Baseboard module:

Low frequency DDS signal source

Function signal

Frequency adjustable from 0.1 to 50KHZ, 10MVp-p to 5Vp-p (continuously adjustable)

Music signal


Modulation signal

The modulation signal and carrier synchronization can display the AM, DSB and FM waveforms on the common oscilloscopes.

Telephone interface


Wireless voice communication can be carried out            

Audio amplifier, speaker


Perform power amplifier output on the receiver's audio signal

DDS high frequency signal source

High frequency sine wave

Frequency range: 1HZ ~ 25MHZ, output amplitude: 100MVp-p to 2Vp-p (continuous adjustable)

Frequency meter


Measurement frequency range: 0-25MHZ, input voltage not less than 50mv;

Frequency sweep meter


Amplitude and frequency characteristics of color LCD display, sweep frequency range, time programmable

Experiment module

Sine wave oscillator and transistor mixing

LC frequency 4-12MHz, can be used to study the amplitude frequency characteristics of the Schiller oscillation circuit and the Clapper oscillation circuit.

Crystal: 8.8MHZ.

Triode mixer circuit: Local oscillator input 8.8MHZ carrier 6.3MHZ, output 2.5MHZ.

Can be completed: Operation point setting, voltage impact on the oscillation frequency, oscillation frequency, high frequency signal amplitude, filter center frequency and other control assessment.

Intermediate release AGC and demodulation module

Amplify the 2.5MHz intermediate frequency signal, and the gain is greater than 20db.

Envelope detection, observe the diagonal cutting distortion and bottom cutting distortion, and low frequency amplification.

Can be completed: Intermediate frequency selection loop, Intermediate release gain, detection distortion, signal output amplitude and other parameters control and assessment.

Resonant circuit module

Single tuning, double tuning, through the varactor to adjust the tuning loop parameters, reliable and stable performance; center frequency 6.3MHZ.

Can be completed: Single tuning double tuning loop parameters, tuning loop frequency-selective characteristics control and assessment.

High frequency power amplifier module

Wireless transmission:

6.3MHZ transmit for base amplitude modulation. Observe the phenomenon of class-C working state of high-frequency power amplifiers, test the tuning characteristics and load characteristics of class-C amplifiers, test the effects of changes in excitation signals, load changes and power supply voltage variations on the operating state, and the cosine pulse waveform can be clearly observed in three states of undervoltage, critical and overvoltage.

Amplitude modulation:

Can be completed: Power amplifier work status control and assessment.

Frequency modulation and capacitance coupling frequency discrimination module

Capacitive coupling loop phase discriminator, slope discriminator 6.3MHZ center frequency.

Synchronous demodulation and integrated mixing (Local oscillator input 8.8MHZ carrier 6.3MHZ, output 2.5MHZ).

Can be completed: FM signal center frequency, signal amplitude, frequency discrimination loop characteristics, operating point parameter control and assessment.

Integrated multiplier amplitude modulation, mixing and synchronous demodulation modules

AM, DSB, SSB modulation and demodulation, carrier frequency 100KHZ-2.5MHZ.

Can be completed: Modulation, modulation signal output, mixing filter and other functional assessment.


Technical parameters

1. The system has built-in DDS low frequency signal source (AM, DSB, FM waveform for function signal, music signal, modulation signal and carrier signal synchronization), microphone signal, DDS high frequency signal source and frequency meter.

1) Low frequency function signal:

Frequency: 100HZ-200KHZ

Amplitude: 0-5Vpp

2) High frequency signal source:

Frequency: 100KHZ-40MHZ

Amplitude: 50mv-2000mvpp

3) Frequency meter:

Frequency range: 0-40MHZ

Amplitude: not less than 50mv

2. Sweeper

The system has a built-in sweep signal source and amplitude phase detection circuit, which can directly display the amplitude and frequency      characteristics of the resonant circuit on the LCD screen.

1) Sweep range: 1MHZ-20MHZ adjustable home, start and stop frequency can be set

2) Sweep time: Programmable

3) Frequency standard instructions: Direct reading bandwidth and resonant peak frequency of mobile frequency standard


Basic experiments

● Small-signal tuning amplifier circuit experiment (including single-tuning and double-tuning)

● Nonlinear Class C Power Amplifier Circuit Experiment

● Three-point oscillator experiment (including LC oscillator and crystal oscillator)

● Intermediate frequency amplifier experiment

● Mixer experiment (including transistor mixing and diode ring mixer)

● Envelope detection and synchronous detection experiments

● Variable capacitance diode frequency modulation experiment

● Discriminator experiment (capacitance couple loop phase discriminator, slope discriminator)

● AM Transmitter Joint Experiment

● AM Receiver Joint Test Experiment

● Transmit and receive complete systems of the intermodulation experiment

● FM transmitter test experiment

● FM receiver joint experiment