Method and apparatus for controlling the frequency of operation and at least one further variable operating parameter of a radio communications device

• US 4,905,305 A
• Filed: 06/30/1989
• Issued: 02/27/1990
• Est. Priority Date: 03/26/1986
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: General Electric Company
• Inventors: Garner, Terry N., Sherman, Ralph R.
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): Kuntz, Curtis
• Application Number:
  US07/373,505
• Time in Patent Office: 242 Days
• Field of Search: 455/114, 455/62, 455/63, 455/67, 455/207-209, 455/183-186, 455/164-166, 455/295, 455/296, 455/314-317, 331/2, 331/18, 331/22, 375/99, 375/111
• US Class Current: 455/183.2
• CPC Class Codes: H03J 5/0281 the digital values being held in an auxiliary non erasable memory
• CPC Class Codes: H04B 1/405 with multiple discrete channels

Abstract

The operating frequency of a radio transceiver and at least one further variable operating parameter of the radio transceiver are controlled in accordance with pre-stored information. Transmit operating radio frequency information is stored in a memory together with associated optimum modulation deviation level information (e.g., so as to maintain a predetermined modulation level at each operating frequency). Receive operating radio frequency information is similarly stored in the memory along with information indicating whether microprocessor clock oscillator frequency is to be shifted (e.g., so as to avoid spurious interfering harmonics emanating from the clock). When operating in the transmit mode, pre-stored modulation gain level information associated with the selected transmit frequency controls the gain of the modulator circuits to compensate for expected changes in modulator circuit gain with change in transmit radio frequency. In the receive mode, the microprocessor clock oscillator frequency may be shifted in accordance with the selected receive frequency, thereby automatically shifting harmonics of the microprocessor clock oscillator out of the receiver bandpass when necessary to avoid locally-generated signals from interfering with signal reception.

Claims

1. In a radio frequency receiving device of the type including:

(1) a tunable radio receiver for receiving radio frequency signals at selected radio frequencies, (2) clock oscillator means for producing a clock synchronizing signal, and (3) a memory, a digital controller synchronized by said clock synchronizing signal communicating with said memory, connected to control said radio receiver and said clock oscillator means, and programmed so as to effect the following functions;

(a) select one of a plurality of radio frequency values stored in said memory;

(b) tune said receiver to receive signals using said selected radio frequency value; and

(c) adjust the frequency of the clock synchronizing signal produced by said clock oscillator means using information associated with said selected radio frequency information stored in said memory to prevent spurious signals generated by said clock oscillator means from interfering with radio frequencies to which said receiver is tuned.

2. A method of controlling a radio receiver of the type including a microprocessor, said method comprising the steps of:

(1) storing information representing a plurality of preset radio frequencies;

(2) storing, for each of said preset radio frequencies, associated corresponding predetermined control information specifying one of at least a first and a second state;

(3) selecting stored information representing one of said preset radio frequencies;

(4) tuning said radio receiver to receive signals at said selected radio frequency using the stored information representing said selected radio frequency;

(5) synchronizing said microprocessor to operate at a first clock frequency if the stored predetermined control information corresponding to said selected radio frequency specifies said first state; and

(6) synchronizing said microprocessor to operate at a second clock frequency different from said first clock frequency if said stored predetermined control information corresponding to said selected radio frequency specifies said second state.

3. A method as in claim 2 wherein:

said synchronizing step (5) includes the step of continuously producing a clock synchronizing signal at a nominal fixed frequency and applying same to said microprocessor; and

said synchronizing step (6) includes the steps of shifting the frequency of said clock synchronizing signal from said nominal fixed frequency to a shifted frequency offset from said nominal frequency when said predetermined stored control information corresponding to said selected radio frequency specifies said second state, and applying said shifted frequency clock signal to said microprocessor.

4. A method as in claim 2 wherein:

said synchronizing step (5) includes the step of operating a crystal oscillator circuit operatively coupled to said microprocessor at a nominal fixed clock frequency determined by the characteristics of a crystal frequency-determining element; and

said synchronizing step (6) includes the step of switching a reactive element into circuit with said crystal frequency-determined element when said stored predetermined control information corresponding to said selected radio frequency specifies said second state to thereby shift the frequency of operation of said oscillator circuit away from said nominal fixed frequency.

5. In a microprocessor-controlled radio receiver of the type including tunable radio receiver means for receiving radio frequency signals at selected controllable radio frequencies a memory, a microprocessor operatively coupled to said memory, and clock oscillator means operatively coupled to said microprocessor for continuously producing a clock synchronizing signal at a nominal fixed clock frequency and applying same to said microprocessor to synchronize the operation of said microprocessor, a method comprising the steps of:

(1) storing information representing a plurality of preset radio frequencies in said memory;

(2) storing in said memory, for each of said preset radio frequencies, predetermined associated corresponding control information specifying one of a normal state and a shifted state;

(3) selecting stored information representing one of said preset radio frequencies;

(4) tuning said radio receiver means to receive signals at said selected radio frequency using the stored information representing said selected radio frequency; and

(5) shifting the frequency of the clock synchronizing signal produced by said clock oscillator means away from said nominal fixed clock frequency if the stored predetermined control information corresponding to said selected radio frequency specifies said shifted state.

6. A method as in claim 5 wherein said shifting step (5) includes the step of shifting the frequency of said clock synchronizing signal from said nominal frequency to a shifted frequency offset from said nominal fixed frequency when said stored predetermined control information corresponding to said selected radio frequency specifies said shifted state, to thereby shift harmonics of said clock synchronizing signal out of the passband of said radio receiver means.

7. A method as in claim 5 wherein:

said method further includes the step of continuously operating said clock oscillator means at a nominal fixed frequency determined by the characteristics of a crystal frequency-determining element; and

said shifting step (5) includes the step of switching a reactance into circuit with said crystal frequency-determining element when said stored predetermined control information corresponding to said selected radio frequency specifies said shift state to thereby shift the frequency of operation of said clock oscillator means away from said nominal fixed frequency.

8. A method as in claim 5 wherein said shifting step (5) includes the steps of:

(a) disabling said clock oscillator means from operating and

(b) enabling a further clock oscillator means also coupled to said microprocessor to operate, said further clock oscillator means producing a clock synchronizing signal at a fixed frequency different from said nominal fixed frequency.

9. An apparatus for controlling a radio receiver of the type including a digital controller, said apparatus comprising:

means for storing information representing a plurality of preset radio frequencies and for also storing, for each of said preset radio frequencies, associated corresponding predetermined control information representing one of a first and a second state;

means for selecting stored information representing one of said preset plurality of radio frequencies;

means for receiving radio frequency signals;

means coupled to said receiving means for tuning said receiving means to receive radio signals at said selected reset radio frequency using said selected stored information; and

means coupled to said digital controller for synchronizing said digital controller to operate at a first clock frequency if the stored predetermined control information corresponding to said selected stored radio frequency information specifies said first state, and for synchronizing said digital controller to operate at a second clock frequency different from said first clock frequency if said stored predetermined control information corresponding to said selected stored radio frequency information specifies said second state.

10. An apparatus as in claim 9 wherein said synchronizing means includes:

oscillator means for continuously producing a clock synchronizing signal at a nominal fixed frequency and for applying said synchronizing signal to said digital controller; and

means operatively connected to said oscillator means for shifting the frequency of said clock synchronizing signal from said nominal fixed frequency to a different frequency when said stored predetermined control information corresponding to said selected stored radio frequency information represents said second state.

11. An apparatus as in claim 9 wherein said synchronizing means includes:

crystal oscillator circuit means, operatively coupled to said digital controller, said oscillator circuit means including a crystal frequency-determining element said oscillator circuit means for continuously operating at a nominal fixed clock frequency determined by the characteristics of said crystal frequency-determining element; and

switching means, coupled to said oscillator means, for switching a reactance into circuit with said crystal frequency-determining element when said stored predetermined control information corresponding to said selected radio frequency information represents said second state to thereby shift the frequency of operation of said oscillator circuit means away from said nominal fixed frequency.

12. In a digitally-controlled radio receiver of the type including a tunable radio receiver receiving radio signals at a programmable radio frequency, a digital controller connected to control said radio receiver, and clock oscillator means operatively coupled to said digital controller for continuously producing a clock synchronizing signal and applying same to said digital controller to synchronize the operation of said digital controller, an improvement comprising:

memory means for storing predetermined information representing a plurality of preset radio frequencies and for storing, for each of said preset radio frequencies associated corresponding preset control information specifying one of a normal state and a shifted state;

means for selecting stored information representing one of said preset radio frequencies;

means for tuning said radio receiver to receive radio signals using said selected stored information; and

means operatively connected to said oscillator means for shifting the frequency of the clock synchronizing signal produced by said clock oscillator means if the stored predetermined control information corresponding to said selected radio frequency information specifies said shifted state.

13. An apparatus as in claim 12 wherein said shifting means includes means for shifting the frequency of said clock synchronizing signal from said nominal fixed clock frequency to a different clock frequency when said stored predetermined control information corresponding to said selected radio frequency information specifies said shifted state, to thereby shift harmonics of said synchronizing signal out of the passband of said receiver.

14. An apparatus as in claim 12 wherein:

said clock oscillator means includes a crystal frequency-determining element for determining the frequency of the clock synchronizing signal produced thereby; and

said shifting means includes means for switching a reactance into circuit with said crystal frequency-determining element when said stored predetermined control information corresponding to said selected radio frequency information specifies said shifted state to thereby shift the frequency of operation of said clock oscillator means away from said nominal fixed frequency.

15. An apparatus, as in claim 12 wherein:

said clock oscillator means is operated at a nominal fixed frequency; and

said shifting means includes;

further clock oscillator means, coupled to said digital controller'"'"' for producing a further clock synchronizing signal of a fixed frequency different from said nominal fixed frequency,

means for disabling said first-mentioned clock oscillator means from operating when said stored preset control information corresponding to said selected radio frequency information specifies said shifted state, and

means for enabling said further clock oscillator means to operate when said stored preset control information corresponding to said selected radio frequency information specifies said shifted state.