Module parameters:

Module model: AD9851

Module type: digital synthesis frequency source

Module power supply: DC-5V

Module current: 70mA (MAX); normal drive current 65mA (TYP)

Module communication protocol: SPI serial or parallel

Module provides routines: STM32F103RCT6

Routine platform: STM32F103X-M3 KEIL5 version source code

Module system main frequency: 180MHz (MAX)

DAC resolution digits: 10 digits

Phase accumulator bits: 32 bits

Module output interface: SMA; 24-hour salt spray anti-oxidation

Module output signals: sine wave, square wave; sine wave with 65MHz low-pass filter. Square wave coupling output.

Module output channel: 2 channel differential; phase difference is 180 degrees, high frequency output will have phase shift due to filter

Signal characteristics of the module: the sine wave has no coupling output; the output has its own DC component. If it is connected to RF equipment, please add a DC blocker or use an oscilloscope to measure directly

Maximum main frequency output sine wave signal range: 1Hz-65MHz

The maximum main frequency output square wave signal range: 1Hz-30MHz; above 10MHz, the oscilloscope input impedance is 50 ohms, and the square wave duty cycle is adjustable.

Output amplitude: sine wave 340mVpp (MAX) square wave 5Vpp; sine wave amplitude decreases with increasing frequency, square wave waveform changes with increasing frequency

Output impedance: 75 ohms

Module features: multiple; high-performance DDS sine wave signal generator, high-order elliptic filter,

Low noise regulator chip, etc.

Module application: multiple; frequency signal generation, sine wave, square wave signal generation, sensor excitation

Module interface type: SMA signal output and external clock input, DC5.5 power socket

Module description:

The AD9851 is a highly integrated device that uses advanced DDS technology, coupled with an internal high-speed, high-performance D/A converter and comparator, to form a digitally programmable frequency synthesizer and clock generator function. When referring to the accurate clock source, the AD9851 generates a stable frequency and performs a phase-programmable digital analog output sine wave. The sine wave can be used directly as a frequency source or internally converted into a square wave agile clock generator application. AD9851 Innovation

The high-speed DDS core accepts 32-bit frequency tuning words, resulting in an output tuning resolution of approximately 0.04 Hz when the system clock is 180 MHz. The AD9851 contains a unique 6 X REFCLK multiplier circuit that eliminates the need for a high-speed reference oscillator. 6 X REFCLK multiplier has minimal effect on SFDR and phase noise characteristics.

Precautions for using the module:

(1) The module is a low-power module, and the power supply does not exceed 5.2V.

(2) Since the module is a high-precision device, in order to avoid unnecessary interference, it is recommended to use a linear power supply.

(3) It is recommended to use the SMA to BNC cable to directly observe the output signal for the output signal. Poor contact or poor quality wires may cause signal attenuation or excessive noise.

(4) The delivered code is only used for the supporting main control board, and does not provide a microcontroller tutorial. Additional functions need to be developed by yourself.

(5) If you need to simply test the function of the module, it is recommended to use it with the control board of our store. Power is supplied to the DDS module first, and then the power is supplied to the control board to generate a waveform. Long press the middle button to switch the function.

Frequently asked questions:

Q: What is the main frequency of the module? Can the output amplitude be adjusted?

A: The main frequency of the module is determined by the input clock and the program. The onboard default clock is 30MHz, and the program control frequency is 6 times, that is, the default frequency is 180MHz. The output amplitude is fixed and there is no way to program it.

Q: Can the module achieve frequency sweep? Is the square wave duty cycle adjustable?

A: The module can realize frequency sweep, the code provided by our store can support frequency sweep. The square wave duty cycle of the module can be adjusted.

Q: Can the two channels be adjusted independently? Can it be modulated?

A: The two channels have a fixed phase difference of 180 degrees, and the frequency is higher. Due to the filter, the phase shift may occur and cannot be adjusted independently. The default code is a point frequency signal, other modes need to be programmed by themselves.