A crystal controlled, digitally programmed frequency synthesizer - 1 kHz to 16.384 MHz with 1 kHz resolution.
A MC145151 PLL synthesizer IC is manually parallel programmed via a 14-bit DIP switch.
Schematic and detailed description are in the Maxim MAX038 High Frequency Waveform Generator datasheet (208k PDF).
Select a picture for larger image.
Front case. Waveform select switch (3-position, center off) is on the left. The waveform select pins require external 10k pull-down (to ground) resistors. Red power LED, 50-ohm RF output is via a BNC connector. On the right side are the DIP switch inputs, binary loaded (in 1 kHz steps) 1 to 8,192. Sync pulse output is on the rear panel via a BNC jack.
Frequency Loading Example
To set the signal generator to 10.7 MHz (N = 10,700) the DIP switches should be set to the following positions:MC145151's N-Divide Pin Voltage: 1 (+5V) = DOWN (OPEN or OFF) DIP Switch Position 0 (GND) = UP (CLOSED or ON) DIP Switch Position
VALUE 1 kHz 2 kHz 4 kHz 8 kHz 16 kHz 32 kHz 64 kHz 128 kHz 256 kHz 512 kHz 1,024 kHz 2,048 kHz 4,096 kHz 8,192 kHz DIP SWITCH 1 2 3 4 5 6 7 8 9 10 11 12 13 14 POSITION ON ON OFF OFF ON ON OFF OFF OFF ON ON OFF ON OFF
So 10,700 kHz (10.7 MHz), in binary, is equal to: 8,192 kHz + 2,048 kHz + 256 kHz + 128 kHz + 64 kHz + 8 kHz + 4 kHz
Internal picture. Refer to the MAX038 datasheet for proper layout considerations.
Close up. MC145151 is on the right side, MAX038 is top left. The MAX412 is the 8-pin surface mount device on the lower left side. Postive and negative voltage regulation and filtering is on top.
Return to Green Bay Professional Packet Radio for more info and contact information.