Zone switching system for a frequency synthesized transceiver

• US 4,403,342 A
• Filed: 04/06/1981
• Issued: 09/06/1983
• Est. Priority Date: 04/06/1981
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Smith, Daniel M., Wieczorek, Alfred B., Borras, Jaime A., Gonzalez, Ruben J.
• Primary Examiner(s): NG, JIN FAY
• Application Number:
  US06/251,644
• Time in Patent Office: 883 Days
• Field of Search: 455/33, 455/76, 455/77, 455/185, 455/186, 455/183
• US Class Current: 455/76
• CPC Class Codes: H03C 3/0933 using fractional frequency division in the feedback loop of the phase locked loop
• CPC Class Codes: H03C 3/0941 applying frequency modulation at more than one point in the loop
• CPC Class Codes: H03C 3/0958 applying frequency modulation by varying the characteristics of the voltage controlled oscillator
• CPC Class Codes: H03C 3/0966 modulating the reference clock
• CPC Class Codes: H03C 3/227 using a combination of bipolar transistors and field effect transistors
• CPC Class Codes: H03D 13/00 Circuits for comparing the phase or frequency of two mutually-independent oscillations measuring phase G01R25/00; phase-discriminators with yes/no output G01R25/005
• CPC Class Codes: H03J 5/0281 the digital values being held in an auxiliary non erasable memory
• CPC Class Codes: H03K 23/667 by switching the base during a counting cycle
• CPC Class Codes: H03L 7/0802 the loop being adapted for reducing power consumption H03L7/14 takes precedence
• CPC Class Codes: H03L 7/193 the frequency divider/counter comprising a commutable pre-divider, e.g. a two modulus divider
• CPC Class Codes: H03L 7/199 with reset of the frequency divider or the counter, e.g. for assuring initial synchronisation
• CPC Class Codes: H04B 1/405 with multiple discrete channels

Abstract

A frequency synthesized transceiver capable of tuning to a plurality of communication channels is disclosed. The transceiver includes a receiver section and a transmitter section which are coupled to the synthesizer which generates the appropriate injection signals to achieve tuning. The frequency synthesizer includes a multiposition switch which accesses various addressable memory locations in a programmable read-only memory where the appropriate divisors are stored to cause tuning of the synthesizer to the appropriate communication channel. A zone selector switch enables grouping and easy retrievability of channels. The divisors are supplied to a single synchronous binary swallow counter which works in conjunction with a dual modulus prescaler to monitor the frequency output of the voltage controlled oscillator. A programmable divider coupled to a reference oscillator source is compared with the output of the synchronous counter in a digital and analog phase detector. The phase detector supplies signals through a loop filter to apply the appropriate voltage to the voltage controlled oscillator. The phase detector includes means to rapid advance the voltage controlled oscillator to cause frequency tuning.

Claims

1. In a radio transceiver including a digital frequency synthesizer and a multiposition switch, addressing frequency channel information stored at a plurality of locations in a memory, for causing the frequency synthesizer to tune to various communication channels, a zone selecting apparatus comprising:

zone selecting means coupled to said memory and establishing at least two distinct and contiguous zones of addressable locations in said memory, all of the locations in a selected zone being addressable by a corresponding number of positions on said multiposition switch,

said zone selecting means operating to alter the correspondence for each successive zone between the positions on said multiposition switch and the corresponding addresses of the memory locations, whereby predetermined channel frequency information may be arbitrarily grouped and stored in any zone of said memory.

2. The zone selecting apparatus of claim 1 wherein said transceiver further includes means to binary encode the selection of the position of said multiposition switch.

3. The zone selecting apparatus of claim 2 wherein said memory is a programmable read-only memory containing information for the tuning of the plurality of communication channels and said transceiver further includes means converting the binary coded selected position of the multiposition switch to correspond to an address in said programmable read-only memory.

4. The zone selecting apparatus of claim 3 wherein said zone selecting means comprises a zone selecting switch and wherein said transceiver further includes means for identifying the selected position of said zone selecting switch with a binary encoded signal and means responsive to the binary encoded signal of said selecting switch to alter addressable locations of said read-only memory corresponding to the binary encoded selectable positions of the multiposition switch may be directed to different zones in said memory.

5. The zone selecting switch of claim 4 wherein the channel information stored in said memory zone corresponding to a position of said zone selecting switch comprises a predetermined arbitrary grouping of said communication channels.

6. The zone selecting apparatus of claim 5 wherein said predetermined grouping of said communication channels is based upon geographic location.

7. The zone selecting apparatus of claim 5 wherein said predetermined grouping of communication channels corresponds to a public service organization constituting the primary users of the communication channels.