GBPPR 1 kHz to 16.384 MHz Synthesized Signal Generator


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.

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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

Pictures

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Internal picture.  Refer to the MAX038 datasheet for proper layout considerations.

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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.

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