All posts in the 'Signal generator' Category
Posted on 04 Aug 2008
Almost all commercially available GPS OEM modules provide a 1pps output, synchronized with GPS time. This pulse could be used as a reference to generate accurate high-frequency clocks, but special design has to address the short-term jitter affecting the 1pps signal. As a general guideline, an oven-stabilized crystal oscillator who guarantees the short-term stability is synchronized with the GPS 1pps for the long-term accuracy.[more]
Posted on 01 Aug 2008
Here is an extremely simple and low cost Sine/Square wave generator based on the Analog Devices AD9835 Direct Digital Synthesis (DDS) Generator chip. The frequency can be set for any frequency from 1Hz to 10MHz in 1Hz resolution steps! All this with three push buttons and a novel “sliding window” LED display. The controller chip is a Microchip PIC16F628. [more]
Posted on 01 Aug 2008
The goal was to build a universal synthesizer usable for transmitting as well as for receiving purposes.The maximum VCO frequency equals to the maximum allowed reference clock input frequency of the DDS chip and are 180MHz for AD9851.[more]
Posted on 01 Aug 2008
The basic analyzer uses two PLL’s mixed together to get a 2-250 MHz output. The PLL’s use Mini-Circuits VCO modules and Motorola MC145191 PLL chips to produce either a fixed 750 MHz or a variable 500-748 MHz output. These two PLL’s operate with a reference frequency of 100 kHz for excellent reference spur rejection and fast lockup times. The two PLL outputs are difference mixed and filtered to produce a 2-250 MHz output. The 1 Hz frequency resolution is achieved by driving the variable PLL’s reference input with the output of a Intersil HSP45102 NCO (Numerically Controlled Oscillator).[more]
Posted on 01 Aug 2008
This covers the band in increments of 0.25Hz and can operate “between the lines” of the Loran interference which is present throughout most of Europe. The design is based on the MiniDDS project by Johan Bodin SM6LKM.This driver uses the Analog Devices AD9832 DDS chip which is controlled by a PIC16F84.[more]