Super Heterodyne Receiver Essay Example | Topics and Well Written Essays - 1000 words

Super Heterodyne Receiver - Essay Example All modern television and radio receivers virtually use the principle of super heterodyne. The super heterodyne receiver reduces to the same intermediate frequency value. In order to accomplish this, it requires that the super heterodyne receiver be able to vary incessantly the frequency that is being mixed into the signal in order to keep the same difference (Jerry 1172). This paper will discuss Super Heterodyne Receiver and its various aspects. History The history of Super Heterodyne Receiver can be traced back to 1905 when Reginald Fessenden, a Canadian inventor, described proposed method to produce an audible signal from an Alexanderson transmitter. However, Edwin Armstrong, a United States Major, devised the principle of super heterodyne receiver in 1918 during the First World War in France. Armstrong invented this device as a way to overcome the deficiencies of early vacuum tube triodes that were being used as high-frequency amplifiers particularly in radio (Drentea 38). These amplifiers were used in equipment for radio direction finding and Armstrong realized that if these receivers could be operated at a much higher frequency, they would be better and more effective. At that time, however, there were no practical short wave amplifiers because of the existing limitations of triodes. Before Armstrong’s invention, it had been noticed that if regenerative receivers were allowed to move into oscillation, it would be possible for other nearby receivers to start picking up stations on frequencies that were different from those that were actually being transmitted on by stations. Several years later, Armstrong deduced that this was as a result of a supersonic heterodyne that was between oscillator frequency and the carrier frequency of the station (Jerry 1173). Therefore, Armstrong realized that that super heterodyne was a potential solution to the amplification problem of short wave. For example, he realized that to monitor 1500 kHz frequency could requ ire setting up an oscillator at 1560 kHz, therefore producing a heterodyne difference of 60 kHz; such a frequency could then be amplified more conveniently by the day’s triodes (Tsui 79). Eventually, Armstrong sold his patent for super heterodyne to Westinghouse, who in turn sold to RCA. RCA later monopolized the super heterodyne receivers market until 1930. Super heterodyne receivers gained more prominence in the 1930s with vacuum tube technology improvements. This situation could also be attributed to the rapid increase in the number of broadcasting stations that created demand for higher-performance and cheaper receivers. Introduction of tubes particularly designed for operation of super heterodyne receivers, notably the pentagrid converter, significantly reduced the advantage that preceding receiver designs had. Commercial production of super heterodyne receivers by the mid-1930s largely replaced the production and use of preceding receivers designs specifically tuned rad io frequency receivers. Eventually, the principle of super heterodyne was virtually taken up for all commercial TV and radio designs (Drentea 102). Design and Operation Principle of Super Heterodyne Receiver The operation principle of super heterodyne receiver mainly relies on the use of frequency mixing or heterodyning. The signal from an antenna is adequately filtered to reject the image frequency (Tsui 90).

Ethics and governance Essay Example | Topics and Well Written Essays - 2000 words - 1

Ethics and governance - Essay Example This left Texas City quite vulnerable to a catastrophe. The decision by the key actors in this BP’s case was founded on the need to ensure that the issue of non-compliance to public safety and health issues by oil companies was addressed. According to Campbell and Tom (2005, p. 551); Davies (2006, p. 106-120) corporations which do not subscribe to the appropriate business ethics do so because they have egoistic inclinations. It is imperative to note that failure to uphold ethics also amounts to lack of effective governance within the affected corporations. Ethics and governance issues in corporations lay the foundation upon which virtues within firms are laid. The action by the Safety and Hazard Investigation Board (CSB) to investigate BP was to audit its safety standards. Hence, this decision was based on the oil fire incident at BP which killed fifteen of its workers and injured a hundred and seventy others. However, the company had ignored this issue for a long time. The report notes that this company was plagued by years of cost cutting which in turn increased its vulnerability to this catastrophe in its refinery in Texas. According to Mortishead, (2005, p. 8); Davies (2006, pp 106-120) the decisions of BP through its management and workers of the company were based on the need to improve its image in the oil industry. From the BP’s case, there are a range of possible consequences based on the report findings. These consequences were changes triggered by the findings in the report. One such consequence is the improvement in the compliance to safety standards by BP and other companies as well. According to Stocker (2005, p. 453-66), in so doing, these oil firms would have to embrace the canons of ethics and governance. In this regard, they shall have to implement fundamental organisational changes to ensure they are virtuous. The other actual consequence is the loss of market leadership position by BP to