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

Pictures

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.