US 7,120,407 B2Granted

Receiver and its tracking adjusting method

AssigneeNiigata Seimitsu Co., Ltd.

InventorHiroshi Miyagi

Life of this patent

Estimating the term…

Loading patent…

Abstract

A receiver such that the period required for tracking adjustment, temperature compensation is not needed, and tracking errors due to fluctuation of the power supply voltage are prevented from increasing, and a tracking adjusting method for the receiver. A DAC 4 generates a voltage according to the value of data (Do) inputted from an MPU 81 by using a control voltage outputted from a low-pass filter 35 in a local oscillator 3 as a reference voltage used during digital-analog conversion. A multiplier circuit 5 analog-multiplies the output voltage of the DAC 4 by a predetermined multiplier. The output voltage of the multiplier circuit 5 is applied as a tuning voltage to a high-frequency tuning circuit 20. In an EEPROM 84 stored is the value of the input data (Do) of the DAC 4 which has been measured in advance and corresponds to the tuned voltage of when the tracking error is the minimum at the central value of the local oscillation frequency, and the MPU 81 reads the data (Do) from the EEPROM 84 and inputs it to the DAC 4.

Claims4

Dependent claims

A tracking adjusting method of performing tracking adjustment of a receiver which comprises:

a high frequency receiving circuit receiving a broadcast wave at a received frequency according to a tuned voltage;
a local oscillator generating a local oscillation signal at a frequency according to a control voltage;
a mixing circuit mixing a signal, which is outputted from the high frequency receiving circuit, and the local oscillation signal, and outputting an intermediate frequency signal corresponding to a differential frequency thereof;
an offset circuit setting a predetermined offset voltage to the control voltage;
and
a multiplier circuit performing analog multiplication of a predetermined multiplier to the control voltage,
and applies a voltage, which is the control voltage passed through the offset circuit and the multiplier circuit, as the tuned voltage to the high frequency receiving circuit, the tracking adjusting method of a receiver characterized in comprising:
a first step of setting a received frequency of the receiver at an arbitrary value included in its variable range and inputting a predetermined test signal having the same frequency as the received frequency at this time into the high frequency receiving circuit;
and
a second step of setting a value of the offset voltage set by the offset circuit so that a tracking error of the receiver after various kinds of settings being performed at the first step may become at a minimum.

7 more elements

A tracking adjusting method of performing tracking adjustment of a receiver which comprises:

a high frequency receiving circuit receiving a broadcast wave at a received frequency according to a tuned voltage;
a local oscillator generating a local oscillation signal at a frequency according to a control voltage;
a mixing circuit mixing a signal, which is outputted from the high frequency receiving circuit, and the local oscillation signal, and outputting an intermediate frequency signal corresponding to a differential frequency thereof;
a digital-to-analog converter which sets the offset voltage by adjusting input data while using the control voltage as a reference voltage;
a multiplier circuit performing analog multiplication of a predetermined multiplier to the control voltage;
memory which stores the input data necessary for generation of the offset voltage set so that a tracking error corresponding to the entire area of a variable range of a frequency of the local oscillation signal may become a predetermined value or less;
and
a voltage value setting unit which sets a value of the offset voltage corresponding to a frequency of the local oscillation signal by reading the input data stored in the memory, and inputting it into the digital-to-analog converter,
and applies a voltage, which is the control voltage passed through the digital-to-analog converter and the multiplier circuit, as the tuned voltage to the high frequency receiving circuit, the tracking adjusting method of a receiver characterized in comprising:
a fourth step of setting a received frequency of the receiver at an arbitrary value included in its variable range and inputting a predetermined test signal having the same frequency as the received frequency at this time into the receiver;
a fifth step of setting input data of the digital-to-analog converter so that a tracking error of the receiver after various kinds of settings being performed at the fourth step may become at a minimum;
and
a sixth step of storing the input data, set at the fifth step, in the memory.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/494,654Filed 16 Nov 2001
Published: US 2005/0003780 A16 Jan 2005
Granted: 10 Oct 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H03L 7/0805
Details of the phase-locked loop: the loop being adapted to provide an additional control signal for use outside the loop
H03J 1/005
For frequency synthesis with counters or frequency dividers: in a loop
H03J 3/24
Continuous tuning: of more than one resonant circuit simultaneously, the circuits being tuned to substantially the same frequency, e.g. for…
H03L 7/099
Details of the phase-locked loop: concerning mainly the controlled oscillator of the loop