In this episode Shahriar explores the principle operation of automotive FMCW radars. Thanks to a donated automotive radar module, various components of the system can be examined and explored. The PCB reveals three die-on-PCB ASICs responsible for generating and receiving 77GHz FMCW signals coupled to a 2D array of antennas. Several microwave components such as rat-race couplers and branchline couplers can also be observed. PCB rulers from SV1AFN Design Lab also show these microwave components at much lower frequencies. Two other ICs are used for ramp generation and PLL as well as a multi-input LNA/PGA/AAF with 12-bit ADC for IF processing. All components are examined under the microscope and the frequency of operation is calculated by measuring the branchline coupler’s dimensions.
Finally a simple Doppler effect radar is constructed by using a doubler, power divider, mixer and a pair of Vivaldi horn antennas. The Doppler effect can be observed by moving an object in front of the antenna pair.
A teardown of piezoelectric buzzer from Electronupdate:
An assembly commonly used on fire, burglar and similar alarm systems.
Based around a piezoelectric disk coupled to a plastic cylinder with a hole on the end (used to amplify the sound).
The controller appears to use a rom-based look up table to generate the sounds
The pattern right below the array almost looks like a series of digital wave forms. I think this is strong evidence of an address decoder.. I presume there is a decoder below each of the columns which actives if the pattern matchs.
Teardown and analysis of Deepace KC901V 6.8GHz handheld network analyzer from the The Signal Path:
In this episode Shahriar reviews the Deepace KC901V 6.8GHz handheld network analyzer. This battery-powered instrument is an RF multi-instrument integrating VNA, spectrum analyzer, field strength meter, and a low-frequency signal generator. It can also perform signal port vector measurement and 2-ports simple vector network analyzing (S11, S21).
Kerry Wong did a teardown of a vintage HP 7044A x-y recorder and programmed an Arduino Due to draw the Lorenz Atrractor using this recorder:
To test the recorder, I wrote a simple program using Arduino Due that generates a Lorenz attractor. The min/max boundaries for each axis were obtained prior and they are used to map the curve to the first quadrant since 7044A can only plot signals within a single quadrant at a time. Arduino Due is convenient because it has two 12bit DAC outputs which can be used to drive the X and Y channel.
Unlike using an oscilloscope, the recorder cannot record data that changes faster than a few Hertz. To slow down the output, you can either decrease the time interval (I chose 0.001) or add in additional delays. I used serial output to slow things down a bit, this is convenient as I could use the data when debugging the program as well.