Specifications

University of Hertfordshire
2
Internet applications, such as Web and this project, are based on the concept of client/server
architecture. Client/server architecture is a kind of network architecture in which each computer or
process on the network is either a client or a server. Clients rely on servers for resources, such as
files, devices, and even processing power. The client/server architecture is not one-to-one. That is, a
single client can access many different servers, and a single server can be accessed by a number of
different clients. Usually, a user runs a client application, such as a Web browser, that contacts one
server at a time to obtain information. To supply information to others, a computer must run a server
application. Although server software can run on any computer, most companies choose large,
powerful computers to run server software because the company expects many clients to be in
contact with its server at any given time. A faster computer enables the server program to return
information with less delay. (Comer, 2000)
TCP/IP builds the infrastructure of the Internet, and client/server architecture provides Internet
applications and services. By using both TCP/IP protocol and client/server architecture, this project
provides a new Internet service.
1.1 Aim and objectives
The aim of the project is to develop a system to control a HP 8591EM Spectrum Analyser remotely
via Internet using a Web browser. The server uses the Linux operating system. It is connected to an
HP 8591 EM Spectrum Analyser via a GPIB interface (or other interfaces). Then client can use web
Browser to control the Spectrum Analyser, and execute some basic function, for example, to set the
start and stop frequency and resolution bandwidth. It should also be possible to set the Spectrum
Analyser to 'zero span' mode on a particular frequency and to feed the demodulated audio output
from the Spectrum Analyser into the server so that it can then be sent to the client using a streaming
audio feed via the Internet. The structural diagram of this project is as follows.