This is a 0~55MHz DDS Signal Generator. It is based on AD9850 chip and is very easy to operate. Supports 0~55MHz continual adjust at 1Hz step. Input 12V (Seller's Note: We are also providing a simplified version, with input 8~9V) With direct digital input frequency With audio volume potentiometer With amp. gain potentiometer With AGC potentiometer S-LED display Standing Wave-LED display Keys & Connection interfaces: ENC: Encoder switch MEM: Switch for memory mode VFO: Transfer from VFO A to VFO B, or from VFO B to VFO A. SSB: Working mode change: circulate from USB, LSB, AM, CW, and on and on... RIT: Fine tuning to receiving frequency CAL: Set functions KB-1 and KB-2 have common shared pin, but is not GND. How to operate: Press CAL, power on, then we enter setting screen. Let go/release CAL. A: ENABLE 6XREFCLE: setting chip clock mode, adjust frequency encoding setting. AD9851 set to 6-multiply frequency, AD9850 set to 1multiply frequency. Press CAL then quickly release to enter next step B. B: DDS-SYSTEM-CLK: Chip working frequency setting. Use encoder switch to adjust value. Operate in accordance with STEP key. AD9851 set at oscillator 6-multiply channel, AD9850 set at actual output of oscillator. Press CAL then quickly release to enter step C. C: MIN_RX_DDS_FREQ: Setting minimum working frequency. Use encoder switch to adjust value and in accordance with STEP key. Press CAL then quickly release to enter step D. D: MAX_RX_DDS_FREQ: Setting maximum working frequency. Use encoder switch to adjust value and in accordance with STEP key. (Smaller than 60MHz would be OK ). Press CAL then quickly release to enter step E. E: SSB_OFFSET: Fine tuning for SSB working mode. Use encoder switch to adjust value and in accordance with STEP key. Press CAL then quickly release to enter step F. F: CW_OFFSET: Fine tuning for CW working mode. Use encoder