Communication receiver system having a voltage converter with an operating frequency below the receiver IF

• US 4,606,076 A
• Filed: 01/07/1985
• Issued: 08/12/1986
• Est. Priority Date: 01/07/1985
• Status: Expired due to Term

• Current Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Davis, Walter L.
• Primary Examiner(s): Bookbinder, Marc E.
• Application Number:
  US06/689,368
• Time in Patent Office: 582 Days
• Field of Search: 455/343, 455/298, 455/299, 455/127, 363/39, 323/354
• US Class Current: 455/343.2
• CPC Class Codes: H04B 1/1607 Supply circuits converters H02M; filters therefor H02M1/14; voltage stabilisers G05F1/46

Abstract

A communication receiver system for receiving coded signals and of the type having at least one predetermined intermediate frequency (IF) signal comprising a decoder for detecting and decoding the received coded signals and a DC/DC voltage converter circuit, connected to the decoder, for generating a voltage greater than the supply voltage of the communication receiver system at a frequency below the frequency of the IF signal. The system further comprises a frequency trim circuit, connected to the voltage converter circuit, for controlling the operating frequency of the DC/DC voltage converter circuit whereby interference with the IF signal is prevented.

Claims

1. A communication receiver system for receiving coded signals and of the type having at least one predetermined intermediate frequency (IF) signal, comprising:

decoder means for detecting and decoding received coded signals;

voltage converter means, connected to said decoder means, for generating a voltage greater than a supply voltage of said communication receiver system, and operating at a frequency below the frequency of the IF signal; and

frequency trim circuit means, connected to said voltage converter means, for controlling the operating frequency of said voltage converter means whereby interference with said IF signal is prevented.

2. A communication receiver system, according to claim 1, wherein said frequency trim circuit means trims the operating frequency of said voltage converter means to a value that is subharmonically unrelated to the frequency of the IF signal.

3. A communication receiver system, according to claim 1, wherein said frequency trim circuit means trims the operating frequency of said voltage converter means whereby there are no harmonics that fall within a predetermined band of frequencies around the frequency of the IF signal.

4. A communications receiver system, according to claim 1, wherein said voltage converter means is a DC/DC voltage converter.

5. A communications receiver system, according to claim 1, wherein said frequency trim circuit means is programmable to either increase or decrease an output current thereof.