{"id":{"repo_id":"rgu","oai_identifier":"oai:rgu-repository.worktribe.com:1993292"},"canonical_url":"https://search.dev.ndltd.org/etd/rgu/oai:rgu-repository.worktribe.com:1993292","repository":{"repo_id":"rgu","name":"Robert Gordon University","base_url":"https://rgu-repository.worktribe.com/oaiprovider"},"display":{"title":"Linearity of some modulation circuits.","abstract":"The work consists of a detailed study of the methods of analogue modulation and demodulation of electrical carrier waves by amplitude and frequency, with the object of presenting improved techniques where necessary. The thesis is divided into five parts, of which the last is devoted to the conclusions. The first and second parts deal with amplitude modulation and demodulation. A novel form of mismatched diode modulator circuit is proposed to improve the linearity of such processes. Developed forms are tested with sinusoidal carrier drive. It is shown that the mismatched demodulator will eliminate distortion due to diagonal clipping. By Fourier analysis it is shown that chopped sine wave modulators, of which there are many types presently used, cannot be deeply modulated and remain linear. The mismatched modulators are re-tested with square wave drive and improved performance is obtained. The third and fourth parts are given to an examination of frequency modulation and demodulation. For applications of low cost, two simple linear frequency modulators are recommended. For receivers, a new theoretical approach to the spectrum of a frequency modulated wave is presented, in which the Bessel series are derived using a straightforward expansion technique. The sensitivity and linearity of the Foster-Seeley type discriminators are investigated in detail.","abstract_html":"The work consists of a detailed study of the methods of analogue modulation and demodulation of electrical carrier waves by amplitude and frequency, with the object of presenting improved techniques where necessary. The thesis is divided into five parts, of which the last is devoted to the conclusions. The first and second parts deal with amplitude modulation and demodulation. A novel form of mismatched diode modulator circuit is proposed to improve the linearity of such processes. Developed forms are tested with sinusoidal carrier drive. It is shown that the mismatched demodulator will eliminate distortion due to diagonal clipping. By Fourier analysis it is shown that chopped sine wave modulators, of which there are many types presently used, cannot be deeply modulated and remain linear. The mismatched modulators are re-tested with square wave drive and improved performance is obtained. The third and fourth parts are given to an examination of frequency modulation and demodulation. For applications of low cost, two simple linear frequency modulators are recommended. For receivers, a new theoretical approach to the spectrum of a frequency modulated wave is presented, in which the Bessel series are derived using a straightforward expansion technique. The sensitivity and linearity of the Foster-Seeley type discriminators are investigated in detail.","abstract_has_math":false,"creators":["Hately, Maurice Clifford"],"institution":"University of Aberdeen; Robert Gordon's Institute of Technology","degree_name":"MSc","degree_level":"Masters","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["T.E. Charlton, J.F. Eastham and J.C. Earls"],"committee_chairs":[],"committee_members":[],"year":1975,"date_issued":"1975","date_published":"1975","updated_at":"2026-07-24T04:10:06Z","subjects":["Amplitude modulation","Modulators (Electronics)","Modulation (Electronics)"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:rgu-repository.worktribe.com:1993292","https://doi.org/10.48526/rgu-wt-1993292"],"render_values":[{"text":"oai:rgu-repository.worktribe.com:1993292","href":null,"code":true},{"text":"https://doi.org/10.48526/rgu-wt-1993292","href":"https://doi.org/10.48526/rgu-wt-1993292","code":true}]}]},"links":{"outbound_url":"https://rgu-repository.worktribe.com/1993292/1/HATELY%201975%20Linearity%20of%20some%20modulation","outbound_label":"Repository record","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["T.E. Charlton, J.F. Eastham and J.C. Earls"]},{"key":"dc:contributor.sponsor","label":"Sponsor","values":["No Funder Acknowledged (Outputs)"]},{"key":"dc:creator","label":"Author","values":["Hately, Maurice Clifford"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["1975-04-30"]},{"key":"dc:date.issued","label":"Date","values":["1975"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Aberdeen; Robert Gordon's Institute of Technology"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://rgu-repository.worktribe.com/output/1993292"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Masters"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["MSc"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Amplitude modulation","Modulators (Electronics)","Modulation (Electronics)"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:rgu-repository.worktribe.com:1993292","https://doi.org/10.48526/rgu-wt-1993292"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://rgu-repository.worktribe.com/1993292/1/HATELY%201975%20Linearity%20of%20some%20modulation"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The work consists of a detailed study of the methods of analogue modulation and demodulation of electrical carrier waves by amplitude and frequency, with the object of presenting improved techniques where necessary. The thesis is divided into five parts, of which the last is devoted to the conclusions. The first and second parts deal with amplitude modulation and demodulation. A novel form of mismatched diode modulator circuit is proposed to improve the linearity of such processes. Developed forms are tested with sinusoidal carrier drive. It is shown that the mismatched demodulator will eliminate distortion due to diagonal clipping. By Fourier analysis it is shown that chopped sine wave modulators, of which there are many types presently used, cannot be deeply modulated and remain linear. The mismatched modulators are re-tested with square wave drive and improved performance is obtained. The third and fourth parts are given to an examination of frequency modulation and demodulation. For applications of low cost, two simple linear frequency modulators are recommended. For receivers, a new theoretical approach to the spectrum of a frequency modulated wave is presented, in which the Bessel series are derived using a straightforward expansion technique. The sensitivity and linearity of the Foster-Seeley type discriminators are investigated in detail."]},{"key":"dc:title","label":"Title","values":["Linearity of some modulation circuits."]}]}],"canonical_facts":{"dc:contributor.advisor":["T.E. Charlton, J.F. Eastham and J.C. Earls"],"dc:contributor.sponsor":["No Funder Acknowledged (Outputs)"],"dc:creator":["Hately, Maurice Clifford"],"dc:date":["1975-04-30"],"dc:date.issued":["1975"],"dc:description.abstract":["The work consists of a detailed study of the methods of analogue modulation and demodulation of electrical carrier waves by amplitude and frequency, with the object of presenting improved techniques where necessary. The thesis is divided into five parts, of which the last is devoted to the conclusions. The first and second parts deal with amplitude modulation and demodulation. A novel form of mismatched diode modulator circuit is proposed to improve the linearity of such processes. Developed forms are tested with sinusoidal carrier drive. It is shown that the mismatched demodulator will eliminate distortion due to diagonal clipping. By Fourier analysis it is shown that chopped sine wave modulators, of which there are many types presently used, cannot be deeply modulated and remain linear. The mismatched modulators are re-tested with square wave drive and improved performance is obtained. The third and fourth parts are given to an examination of frequency modulation and demodulation. For applications of low cost, two simple linear frequency modulators are recommended. For receivers, a new theoretical approach to the spectrum of a frequency modulated wave is presented, in which the Bessel series are derived using a straightforward expansion technique. The sensitivity and linearity of the Foster-Seeley type discriminators are investigated in detail."],"dc:identifier":["oai:rgu-repository.worktribe.com:1993292","https://doi.org/10.48526/rgu-wt-1993292"],"dc:identifier.uri":["https://rgu-repository.worktribe.com/1993292/1/HATELY%201975%20Linearity%20of%20some%20modulation"],"dc:language":["en"],"dc:publisher.institution":["University of Aberdeen; Robert Gordon's Institute of Technology"],"dc:relation.isreferencedby":["https://rgu-repository.worktribe.com/output/1993292"],"dc:subject":["Amplitude modulation","Modulators (Electronics)","Modulation (Electronics)"],"dc:title":["Linearity of some modulation circuits."],"dc:type":["Thesis"],"dc:type.qualificationlevel":["Masters"],"dc:type.qualificationname":["MSc"]},"updated_at":"2026-07-24T04:10:06Z"}