Circuit arrangement for digital frequency indication in a radio receiver

US3949307A · kind A · utility

Assignee

• Licentia Patent-Verwaltungs-GmbH · DE

Inventors

• Otto Klank · Burgdorf, DE
• Dieter Rottmann · Hannover, DE

Key dates

• Filing date: Nov 21, 1974
• Grant date: Apr 6, 1976
• Expiry date: Nov 21, 1994

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03K23/66
• WIPO field: Basic communication processes
• WIPO sector: Electrical engineering

Abstract

In a circuit arrangement for digitally indicating the tuned frequency of a radio receiver operating in the AM and FM ranges in which the oscillations of the AM tuning oscillator and of the FM tuning oscillator are amplified, converted to rectangular oscillations, counted by means of electronic counters and then digitally displayed, the oscillations of the AM tuning oscillator and the oscillations of the FM tuning oscillator are amplified by a common broadband amplifier which is sufficiently broadbanded so that the oscillator frequencies for the AM range as well as those for the FM range are both passed and amplified and the coupling of the input of the broadband amplifier to the outputs of the tuning oscillators is so loose that the tuning oscillators are not noticeably detuned by changes in capacity in the broadband amplifier.