AD633 for multiplier

Vamsi suggests using Analog Devices' AD633 as the multiplier in our project. The circuit consists of a standard implementation mentioned in the datasheet. (Fig. 3).



Specifications

Transfer Function		[(X1–X2)(Y1–Y2)/10] + Z
Slew Rate (V/µs		20V/µs
Supply Voltage (V max)		±18V
Supply Current (max)		6mA
Temp Range		-40 to 85°C
Package		DIP/SOIC

From Analog Devices website. The datasheet.

AD633 seems cheap, and very popular. Good for it. Also, AD seem very forthcoming to give free samples. I will try something about that.

The development board for PIC18F2455

The previous post contains the link to the datasheet of the PIC18F2455. That thing is huge, some 428 pages. Instead, here is the link to the development board of the same controller. With the development board, I hope, it will be easier to handle USB protocols. (Without it, it seems simply impossible). I havn't been able to fix myself on either of the modules till now. The options are:
1)the dlpdesign module that mandar discussed
2)this PIC module
3)Since I am comfortable with the 8051 architecture, I would like to use a 8051 based controller, am trying to find a suitable one. Any help will be appreciated :-)

Here is the link:
http://www.sparkfun.com/commerce/product_info.php?products_id=762

Using a USB PIC

The USB microcontroller I have in mind is the PIC 18F2455.

Here is the link for the datasheet. ww1.microchip.com/downloads/en/DeviceDoc/39632b.pdf

This microcontroller not only offers upto 8MHz internal clock, but also has features like setting a self sampling rate through software, an inbuilt ADC (not sure if we can use it though). It provides for having 2 different rates for running the controller and for USB data transfer!

Dipole Antenna

Hi guys,
I have got 1kg (~50m) of aluminium wire (gauge 12) for making the dipole antenna. I got a good deal for Rs. 230/-. Copper wire is pretty expensive and 16m will cost Rs. 800/-. We can buy the copper wire whenever needed. We would be making a wooden stand in the workshop soon.

Virtual COM ports, and Noise Generation

Contacted my instructor at IGCAR today regarding use of the DLP245M module.He says the data rate of 8 Mbps should hold for our signal, but suggested that the transfer from the module to the computer might not be that fast.Therefore, we might have to investigate use of a larger buffer for storing the 8-bit data after acquisition.

A good thing for possible coding in C language is the VCP (Virtual COM port) feature in the DLP 245BM. This makes the module look like another COM port to the PC, but without the speed restrictions.According to the datasheet,

"Commands to set the baud rate are ignored – the device always transfers data at its fastest rate regardless of the
application’s baud rate setting. The latest versions of the drivers are available for download from DLP Design’s website at http://www.dlpdesign.com."

According to what I have heard recently from Amit, reading data from a COM port in C is possible. So, this could give us our basic acquisition system. <Still a bit confused about the data rate mentioned in the datasheet..8 million bits per second....i.e.1 MBps.. Does it mean that data can be sampled at that rate or that data is only transferred to the computer at that rate?..>

Still at a low regarding generation of random data for noise centered around a particular frequency in C. Forums on DSP pretty silent about noise generation around a particular frequency. I might try doing it in MATLAB next week.

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Comedi for errors !

Software lib for possible use. hat tip Mandar...

Index Introduction Download Documentation Mailing list Supported hardware Manufacturers Applications Bug Tracking Links Linux Debian RTAI David Schleef

Introduction The Comedi project develops open-source drivers, tools, and libraries for data acquisition. Comedi is a collection of drivers for a variety of common data acquisition plug-in boards. The drivers are implemented as a core Linux kernel module providing common functionality and individual low-level driver modules. Comedilib is a user-space library that provides a developer-friendly interface to Comedi devices. Included in the Comedilib distribution is documentation, configuration and calibration utilities, and demonstration programs. Kcomedilib is a Linux kernel module (distributed with Comedi) that provides the same interface as Comedilib in kernel space, suitable for real-time tasks. It is effectively a "kernel library"

USB port card

Mandar has a very good idea of using a USB port based acquisition. Below are details of DLP-IO8-G 8-Channel Data Acquisition Board and DLP-USB245M USB Adapter, from this link and that link. Other similar option from DLP is DLP-TXRX-G USB Adapter.


DLP-IO8-G 8-Channel Data Acquisition Board

		DOWNLOADS Test Application V1.0 VCP Drivers FTDI Driver Installation Ap Note for Win98 FTDI Driver Installation Ap Note for Win 2000
	8 Channels: Digital I/O, Analog In, Temperature (requires DS18B20 sensor, purchased separately) Easy to use single byte commands USB 1.1, 2.0 Compatible Rev 2 silicon from FTDI No in-depth knowledge of USB required Call or email DLP Design for volume pricing

DLP-USB245M USB Adapter

		DOWNLOADS Test Application V1.0 DLL Drivers DLL Driver Programmer's Guide VCP Drivers FTDI Driver Installation Ap Note for Win98 FTDI Driver Installation Ap Note for Win 2000
	Add USB connectivity to your next project Up to 8 megabit per second data rate USB 1.1 Compliant Simple FIFO interface to MCU/FPGA/CPU/etc... Rev 2 silicon from FTDI No in-depth knowledge of USB required Call or email DLP Design for volume pricing