02-11-2012, 05:14 PM
XR-2206 Monolithic Function Generator
[attachment=37961]
FEATURE
Low-Sine Wave Distortion, 0.5%, Typical
Excellent Temperature Stability, 20ppm/°C, Typ.
Wide Sweep Range, 2000:1, Typical
Low-Supply Sensitivity, 0.01%V, Typ.
Linear Amplitude Modulation
TTL Compatible FSK Controls
Wide Supply Range, 10V to 26V
Adjustable Duty Cycle, 1% TO 99%
GENERAL DESCRIPTION
The XR-2206 is a monolithic function generator
integrated circuit capable of producing high quality sine,
square, triangle, ramp, and pulse waveforms of
high-stability and accuracy. The output waveforms can be
both amplitude and frequency modulated by an external
voltage. Frequency of operation can be selected
externally over a range of 0.01Hz to more than 1MHz.
The circuit is ideally suited for communications,
instrumentation, and function generator applications
requiring sinusoidal tone, AM, FM, or FSK generation. It
has a typical drift specification of 20ppm/°C. The oscillator
frequency can be linearly swept over a 2000:1 frequency
range with an external control voltage, while maintaining
low distortion.
SYSTEM DESCRIPTION
The XR-2206 is comprised of four functional blocks; a
voltage-controlled oscillator (VCO), an analog multiplier
and sine-shaper; a unity gain buffer amplifier; and a set of
current switches.
The VCO produces an output frequency proportional to
an input current, which is set by a resistor from the timing
terminals to ground. With two timing pins, two discrete
output frequencies can be independently produced for
FSK generation applications by using the FSK input
control pin. This input controls the current switches which
select one of the timing resistor currents, and routes it to
the VCO.
Sine Wave Generation
Without External Adjustment
Figure 11 shows the circuit connection for generating a
sinusoidal output from the XR-2206. The potentiometer,
R1 at Pin 7, provides the desired frequency tuning. The
maximum output swing is greater than V+/2, and the
typical distortion (THD) is < 2.5%. If lower sine wave
distortion is desired, additional adjustments can be
provided as described in the following section.
The circuit of Figure 11 can be converted to split-supply
operation, simply by replacing all ground connections
with V-. For split-supply operation, R3 can be directly
connected to ground.
Triangle Wave Generation
The circuits of Figure 11 and Figure 12 can be converted
to triangle wave generation, by simply open-circuiting Pin
13 and 14 (i.e., S1 open). Amplitude of the triangle is
approximately twice the sine wave output.
FSK Generation
Figure 13 shows the circuit connection for sinusoidal FSK
signal operation. Mark and space frequencies can be
independently adjusted by the choice of timing resistors,
R1 and R2; the output is phase-continuous during
transitions. The keying signal is applied to Pin 9. The
circuit can be converted to split-supply operation by
simply replacing ground with V-.
Amplitude Modulation:
Output amplitude can be modulated by applying a dc bias
and a modulating signal to Pin 1. The internal impedance
at Pin 1 is approximately 100k. Output amplitude varies
linearly with the applied voltage at Pin 1, for values of dc
bias at this pin, within 14 volts of VCC/2 as shown in
Figure 6. As this bias level approaches VCC/2, the phase
of the output signal is reversed, and the amplitude goes
through zero. This property is suitable for phase-shift
keying and suppressed-carrier AM generation. Total
dynamic range of amplitude modulation is approximately
55dB.
[attachment=37961]
FEATURE
Low-Sine Wave Distortion, 0.5%, Typical
Excellent Temperature Stability, 20ppm/°C, Typ.
Wide Sweep Range, 2000:1, Typical
Low-Supply Sensitivity, 0.01%V, Typ.
Linear Amplitude Modulation
TTL Compatible FSK Controls
Wide Supply Range, 10V to 26V
Adjustable Duty Cycle, 1% TO 99%
GENERAL DESCRIPTION
The XR-2206 is a monolithic function generator
integrated circuit capable of producing high quality sine,
square, triangle, ramp, and pulse waveforms of
high-stability and accuracy. The output waveforms can be
both amplitude and frequency modulated by an external
voltage. Frequency of operation can be selected
externally over a range of 0.01Hz to more than 1MHz.
The circuit is ideally suited for communications,
instrumentation, and function generator applications
requiring sinusoidal tone, AM, FM, or FSK generation. It
has a typical drift specification of 20ppm/°C. The oscillator
frequency can be linearly swept over a 2000:1 frequency
range with an external control voltage, while maintaining
low distortion.
SYSTEM DESCRIPTION
The XR-2206 is comprised of four functional blocks; a
voltage-controlled oscillator (VCO), an analog multiplier
and sine-shaper; a unity gain buffer amplifier; and a set of
current switches.
The VCO produces an output frequency proportional to
an input current, which is set by a resistor from the timing
terminals to ground. With two timing pins, two discrete
output frequencies can be independently produced for
FSK generation applications by using the FSK input
control pin. This input controls the current switches which
select one of the timing resistor currents, and routes it to
the VCO.
Sine Wave Generation
Without External Adjustment
Figure 11 shows the circuit connection for generating a
sinusoidal output from the XR-2206. The potentiometer,
R1 at Pin 7, provides the desired frequency tuning. The
maximum output swing is greater than V+/2, and the
typical distortion (THD) is < 2.5%. If lower sine wave
distortion is desired, additional adjustments can be
provided as described in the following section.
The circuit of Figure 11 can be converted to split-supply
operation, simply by replacing all ground connections
with V-. For split-supply operation, R3 can be directly
connected to ground.
Triangle Wave Generation
The circuits of Figure 11 and Figure 12 can be converted
to triangle wave generation, by simply open-circuiting Pin
13 and 14 (i.e., S1 open). Amplitude of the triangle is
approximately twice the sine wave output.
FSK Generation
Figure 13 shows the circuit connection for sinusoidal FSK
signal operation. Mark and space frequencies can be
independently adjusted by the choice of timing resistors,
R1 and R2; the output is phase-continuous during
transitions. The keying signal is applied to Pin 9. The
circuit can be converted to split-supply operation by
simply replacing ground with V-.
Amplitude Modulation:
Output amplitude can be modulated by applying a dc bias
and a modulating signal to Pin 1. The internal impedance
at Pin 1 is approximately 100k. Output amplitude varies
linearly with the applied voltage at Pin 1, for values of dc
bias at this pin, within 14 volts of VCC/2 as shown in
Figure 6. As this bias level approaches VCC/2, the phase
of the output signal is reversed, and the amplitude goes
through zero. This property is suitable for phase-shift
keying and suppressed-carrier AM generation. Total
dynamic range of amplitude modulation is approximately
55dB.