Digitally-corrected temperature-compensated crystal oscillator having a correction-suspend control for communications service

[5. A digitally-corrected temperature compensated crystal oscillator (DTCXO) having an output and a control input, comprising:

• means for generating a free-running frequency signal connected to the output, comprising a piezoelectric crystal oscillator having a bank of trimming capacitors controlled by switches such that a digital code presented to said switches will cause said DTCXO to vary in output frequency;
• means for detecting an ambient temperature proximate to the frequency generating means, comprising an ambient temperature sensor and a analog-to-digital converter;
• means for adjusting said free-running frequency signal responsive to the detection means and connected to the frequency generating means, comprising a programmable read only memory responsive to the temperature detecting means and a latch connected to the frequency generating means;
• and
• means to suspend the adjusting means such that a last valid adjustment value is held during a period of suspension, the suspension means responsive to the control input and connected to the frequency adjusting means.]

[7. A radio communications unit, comprising:

• at least one digitally-corrected temperature-compensated crystal oscillator (DTCXO) having an output and a control input, having:
• (a) means for generating a free-running frequency signal connected to the output, comprising a piezoelectric crystal oscillator having a bank of trimming capacitors controlled by switches such that a digital code presented to said switches will cause said DTCXO to vary in output frequency;
• (b) means for detecting an ambient temperature proximate to the frequency generating means, comprising an ambient temperature sensor and a analog-to-digital converter;
• (c) means for adjusting said free-running frequency signal responsive to the detection means and connected to the frequency generating means, comprising a programmable read only memory responsive to the temperature detecting means and a latch connected to the frequency generating means;
• and
• (d) means to suspend the adjusting means such that a last valid adjustment value is held during a period of suspension, the suspension means responsive to the control input and connected to the frequency adjusting means.
• means for receiving communications responsive to a signal from the DTCXO.]

[10. A method for improving the quality of electronic telecommunications in a multi-mode communication means utilizing an oscillator having a temperature compensation means to update a value based upon detected temperature at said oscillator and, via adjustment means, change the frequency of oscillation of said oscillator to a predetermined frequency of oscillation based upon said updated value, comprising the steps of:

• detecting which, if any, modes of electronic telecommunication are active;
• suspending the updating by said temperature compensation means upon detection of an active mode to prevent said updating from generating interference that can degrade the operation of the active mode of said communications means;
• providing a delay period commencing from the point in time when updating last occurred;
• and
• updating said temperature compensation means value after the expiration of the delay period whether or not an active mode is detected.]

[12. A method for improving the quality of communications in a cellular telephone having modes comprising transmission, message encoding, reception, and message decoding, the telephone utilizing an oscillator having a temperature compensation means to update a value based upon detected temperature at said oscillator and, via adjustment means, change the frequency of oscillation of said oscillator to a predetermined frequency of oscillation based upon said updated value, comprising the steps of:

• detecting which, if any, modes of electronic telecommunication are active;
• suspending the updating by said temperature compensation means upon detection of an active mode to prevent said updating from generating interference that can degrade the operation of the active mode of said cellular telephone;
• providing a delay period commencing from the point in time when updating last occurred;
• and
• updating said temperature compensation means value after the expiration of the delay period whether or not an active mode is detected.]

[13. A computer-implemented process for improving electronic communications in a radio having a microprocessor, comprising the following steps:

• detecting whether or not at least one mode of electronic communication is active, said modes comprising transmission, message encoding, reception, and message decoding;
• suspending an updating of a temperature compensation correction word in an oscillator system providing reference frequencies that are supporting said electronic communications, such that interference and errors otherwise generated by said updating of said temperature compensation correction word will not be induced during the time activity of said mode is detected;
• and
• waiting a timeout period from a point of last inactivity of said mode and then forcing the updating of said temperature compensation correction word in said oscillator system.]

[14. A method for improving receiver sensitivity and for reducing power consumption in a telephone pager utilizing an oscillator having a temperature compensation means to update a value based upon detected temperature at said oscillator and, via adjustment means, change the frequency of oscillation of said oscillator to a predetermined frequency of oscillation based upon said updated value, comprising the steps of:

• detecting when the pager is in a standby mode of operation;
• suspending the updating by said temperature compensation means upon detection of said standby mode to prevent said temperature compensation updating means from generating interference that can deteriorate the receiver sensitivity of the pager and from consuming power;
• providing a delay period commencing from the point in time when updating last occurred;
• and
• updating said temperature compensation means value after the expiration of
• the delay period whether or not an active mode is detected.]

A digitally-corrected, temperature-compensated crystal oscillator circuit having an output terminal and a control input terminal inputting an external control signal indicating a state of a communication circuit, said digitally-corrected, temperature-compensated crystal oscillator circuit, comprising:

• an oscillator circuit generating a frequency signal, the frequency signal output on the output terminal;
• a compensation circuit connected to the oscillator, wherein a frequency of the frequency signal is based on a state of the compensation circuit;
• a temperature sensor circuit detecting an ambient temperature and outputting a temperature signal based on the detected ambient temperature;
• a conversion circuit connected to the temperature sensor circuit and the compensation circuit and inputting the temperature signal and outputting a ready signal and a compensation signal, the state of the compensation circuit based on the compensation signal;
• and
• a control circuit connected to the conversion circuit and inputting the external control signal and outputting a control signal to the conversion circuit only when the external control signal indicates that the communication circuit is not active and the ready signal is generated by the conversion circuit, the conversion circuit updating the compensation signal based on the control signal.

A communication unit, comprising:

• an oscillator circuit outputting a pulse signal;
• a temperature sensor circuit outputting a temperature signal indicative of a sensed temperature;
• a temperature conversion circuit outputting a ready signal and a temperature compensation signal based on the temperature signal;
• a temperature compensation circuit, wherein a state of the temperature compensation circuit is based on the temperature compensation signal, the state of the temperature compensation circuit adjusting a frequency of the pulse signal output by the oscillator circuit;
• and
• a communication circuit inputting the pulse signal, wherein based on an operating state of the communication circuit and generation of the ready signal by the temperature conversion circuit, an update of the adjustment of the frequency of the pulse signal by the temperature compensation
• circuit is suspended.

A communications unit, comprising:

• an oscillator circuit outputting pulse signal;
• a communications circuit inputting the pulse signal of the oscillator circuit, wherein the communications circuit alternates, periodically, between a receive state and a standby state, the communications circuit outputting an external control signal based on the state of the communications circuit;
• a temperature sensor circuit outputting a temperature signal indicative of a sensed temperature;
• a temperature conversion circuit inputting the temperature signal and outputting a ready signal and a temperature compensation signal based on the temperature signal;
• a temperature compensation circuit, wherein a state of the temperature compensation circuit is based on the temperature compensation signal, the state of the temperature compensation circuit adjusting a frequency of the pulse signal output by the oscillator circuit;
• and
• a control circuit inputting the external control signal and outputting a control signal to the temperature conversion circuit to operate the temperature conversion circuit to update the state of the temperature compensation circuit only when the communications circuit is in the standby state and the ready signal is generated by the temperature conversion circuit, wherein the control circuit is prevented from outputting the control signal to the temperature conversion circuit when the external control signal indicates that the communications circuit is in the receive state.

A time division multiple access communications unit, comprising:

• an oscillator circuit outputting a pulse signal;
• a time division multiple access communications circuit inputting the pulse signal of the oscillator circuit, wherein the communications circuit has receive operation periods, send operation periods, and idle periods, the communications circuit outputting an external control signal;
• a temperature sensor circuit outputting a temperature signal indicative of a sensed temperature;
• a temperature conversion circuit outputting a ready signal and a temperature compensation signal based on the temperature signal;
• a temperature compensation circuit, wherein a state of the temperature compensation circuit is based on the temperature compensation signal, the state of the temperature compensation circuit adjusting a frequency of the pulse signal output by the oscillator circuit;
• and
• a control circuit inputting the external control signal and outputting a control signal to the temperature conversion circuit to operate the temperature conversion circuit to update the state of the temperature compensation circuit only when the communications circuit is in said idle periods and the ready signal is generated by the temperature conversion circuit, wherein the control circuit is prevented from outputting the control signal to the temperature conversion circuit when the external control signal indicates that the communications circuit is in one of a receive operation period or a send operation period.

A compensated oscillator, comprising:

• an oscillator circuit outputting a pulse signal;
• a compensation signal generating circuit outputting a compensation signal and a ready signal;
• a compensation circuit, wherein a state of the compensation circuit is based on the compensation signal, the state of the compensation circuit adjusting a frequency of the pulse signal output by the oscillator circuit;
• and
• a control circuit inputting an external control signal and outputting a control signal to the compensation signal generating circuit to operate the compensation signal generating circuit to output the compensation signal to update the state of the compensation circuit, wherein, the control circuit is prevented from outputting the control signal when the external control signal indicates that a communication circuit that uses said pulse signal is active and the ready signal is not generated by the compensation signal generating circuit.

A communication unit, comprising:

• an oscillator circuit outputting a pulse signal;
• a compensation signal generating circuit outputting a compensation signal and a ready signal;
• a compensation circuit, wherein a state of the compensation circuit is based on the compensation signal, the state of the compensation circuit adjusting a frequency of the pulse signal output by the oscillator circuit;
• and
• a communication circuit inputting the pulse signal, wherein, based on an operating state of the communication circuit and generation of the ready signal by the compensation signal generating circuit, an update of the adjustment of the frequency is suspended.