Description
MICROPROCESSOR CONTROLLED 87.50 ~ 108.00 MHz BROADCASTING FM RADIO GENERATOR/DRIVER WITH GRAPHICS DISPLAY ( 2 UNITS). Operating frequency 87.50 to 108.00 MHz Frequency step 50KHz Frequency entry through rotary encoder with lock 128 X 64 Dotmatrix display Modulation level indication RF power output and V.S.W.R. in watts ,all shown on LCD module. RF module in shielded metal box RF output level +20dBm/50 ohm(+-1.5dB flatness)Modulation signal input flat to accept all kinds of analog/complex digital signals Minicircuits 5stage low pass filter Very low spurious/noise,better than -113dBc/Hz First harmonic rejection better than 50dBc,second better than 60 dBc The two modules are connected with a flat ribbon cable 50cm long,can be instantly disconnected/removed. Operating voltage 12.5V DC/260mA both units Dimentions,display unit: 12X7X3 cm,RF unit : 13X7X3 cm *The Units were licenced/registered within professional exciter sets(the only missing are a final amplifier and power supply…) * Microprocessor/display unit has three inputs,one for the modulated signal,one for the final amplifier transmitted RF power and the VSWR level,both are displayed in watts.There are 3 presets on the backside of the p.c.board so that the display indications can be adjusted to individual existing conditions.For the modulation signal,there is an additional anplifying stage on board in order to help adjusting the proper signal level to be indicated on the LCD. The other two signals are DC voltage derived from the rectified RF levels of the exciter output bridge. The processor is programmed for indication of RF power to 60 watts,there is provision for higher power levels,just ASK for it upon ordering. In order to change/set the desired frequency,the rotary encoder shaft is pushed for more than 10 seconds ,then the letters”MHz” start flashing and the frequency entry can be acomplished. When the PLL is locked, the word “LOCK” appears on the LCD,if it doesn’t of is flashing,then the PLL is not locked. When frequency is locked,certain pin on the display board becomes high,this can be used to activate the following RF amplifier so carrier will be present ONLY when selected frequency is locked. The units are made for 100% duty cycle,the only requirement is the supply voltage to be well stabilised and noise/hum free…
