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NOTE£ºThe product needs to be connected to a 9V power supply (but cannot use a 9V battery)!!
Features :
This is a 0~55MHz DDS Signal Generator. It is based on AD9850 chip and is very easy to operate.
Supports 0~55MHz continual adjust at 1Hz step.
This generator has 78L05 voltage regulate. Input current at 200MA, input voltage 8-9V would be the ideal voltage.
Input voltage of 12V can only be used for short time testing, otherwise will cause heat to board.
5p/6p connect to encoder as per photo. 7p of the middle connects to digital matrix input. 14p (8V GND) is 8V power supply from main board. If powered by main board, DDS does not need independent power supply.
1~6 correspond to 6 frequency bands: (3.8,7 ,9,14,18 or 21,27 or 29)
ISB, USB, CW are the three mode choices.
DT is signal from main board.
Keys & Connection interfaces:
ENC: encoder switch
MEM: switch for memory mode
VFO: Transfer from VFO A to VFO B, or from VFO B to VFO A.
SSB: Working mode change: circulate from USB, LSB, AM, CW, and on and on...
RIT: fine tuning to receiving frequency
CAL: set functions
KB-1 and KB-2 have common shared pin, but is not GND.
How to operate:
Press CAL, power on, then we enter setting screen. Let go/release CAL.
A: ENABLE 6XREFCLE: setting chip clock mode, adjust frequency encoding setting. AD9851 set to 6-multiply frequency, AD9850 set to 1multiply frequency. Press CAL then quickly release to enter next step B.
B: DDS-SYSTEM-CLK: Chip working frequency setting. Use encoder switch to adjust value. Operate in accordance with STEP key. AD9851 set at oscillator 6-multiply channel, AD9850 set at actual output of oscillator. Press CAL then quickly release to enter step C.
C: MIN_RX_DDS_FREQ:Setting minimum working frequency. Use encoder switch to adjust value and in accordance with STEP key. Press CAL then quickly release to enter step D.
D: MAX_RX_DDS_FREQ:Setting maximum working frequency. Use encoder switch to adjust value and in accordance with STEP key. (Smaller than 60MHz would be OK ). Press CAL then quickly release to enter step E.
E: SSB_OFFSET:Fine tuning for SSB working mode. Use encoder switch to adjust value and in accordance with STEP key. Press CAL then quickly release to enter step F.
F: CW_OFFSET:Fine tuning for CW working mode. Use encoder switch to adjust value and in accordance with STEP key. Press CAL then quickly release to enter step G.
G: OFFSET_FREQ:Setting of offset Frequency. e.g, set to 9MHz or 10.7MHz, use encoder switch to adjust value and in accordance with STEP key. Press CAL then quickly release to enter step H.
H: MULTIPLIER: multiply setting for frequency. Should be set as 1, press CAL then quickly release to enter step I:
I: Screen displayes word "SAVE", automatically save the above setting, and returns to normal working.
Notes:
1. DDS SYSTEM CLK: can use frequency tester to get 30MHz oscillator, multiply the tested value at 6, then put the multiplied value here. If using AD9851, make initial setting at 180000000.
2. OFFSET FREQ: can be set as + or - . Rotate encoder switch to change value, press STEP key, then rotate encoder switch to adjust step. Minimum working frequency plus (+) offset frequency should be high than 0 (zero).
Frequency display:
RX = MULTIPLIER x (RX_DDS_FREQ + OFFSET_FREQ)
TX = MULTIPLIER x (RX_DDS_FREQ + OFFSET_FREQ + TX_OFFSET_FREQ)
The frequency programmed into the DDS, is calculated as shown below.
RX = ABS(RX_DDS_FREQ)
TX = ABS(RX_DDS_FREQ + TX_OFFSET_FREQ)
RX_DDS_FREQ, MIN_RX_DDS_FREQ, MAX_RX_DDS_FREQ, TX_OFFSET_FREQ & OFFSET_FREQ
Examples:
1. DDS output range 30~40MHz:
MIN_RX_DDS_FREQ MAX_RX_DDS_FREQ OFFSET_FREQ RX Frequency display range.
30 MHZ 40 MHz 100 MHz = 130 MHz to 140 MHz. \ Note 1
30 MHZ 40 MHz -10 MHz = 20 MHz to 30 MHz. /
-40 MHZ -30 MHz 170 MHz = 140 MHz to 130 MHz. \ Note 2
-40 MHZ -30 MHz 60 MHz = 30 MHz to 20 MHz. /
2. setting FT180A with DDS:
ENABLE RPT NO
X6 RECLK X6
DDS SYSTEM CLK 180M
MAX DDS FREQ 65M
MIN RX DDS FREQ 10.701M (Offset frequency + RIT frequency)
MAX RX DDS FREQ 60M
TX OFFSET FREQ 0
MAX RIT OFFSET 1K (RIT frequency)
OFFSET FREQ £10.700M £(Offset frequency)
MULTIPLIER 1
Package Content:
1 x AD9850 6 Bands 0~55MHz DDS Signal Generator Digital HAM Radio RIT VFO SSB
More
Introduction
1.. Wiring method of external buttons:
In the above figure, KB-2 and KB-1 are external button interfaces. The first pin on the leftmost side is the common pin of the respective interface. They are connected to a total of four pins to complete their respective functions, such as KB-1: 1 -2 is connected to complete the control conversion function of the working mode, such as KB-1: 1-4 is connected to enter the stepping adjustment state.
The ENC in the figure above is the pin of the encoding switch. Among them, the switch A in the figure below is connected to the second pin of KB-2, the B in the figure below is connected to the third pin of KB-2, and the C in the figure below is connected to the second pin of KB-2. 1 foot.
2. Regarding the control function of working mode and band
Due to the limited drive capability of the single-chip microcomputer or the different working voltage of the external relay, the relay cannot be directly driven. The drive that requires the working mode and working band requires an external drive circuit. For specific circuits, please refer to other materials.
3. LCD backlight connection
Considering that some friends may use their own LCD display screens, it may be because the LED backlight polarity is different, so on the PCB, pins 15 and 16 are suspended. Please connect them according to the LCD polarity used.
The LCD backlight connection method provided by me, 16 pins are grounded, and 15 pins are connected in series with a 51 ohm resistor to the power supply +5V. If you want to turn off the backlight at any time, you can connect a switch to control +5V.
4. Debugging of DDS
The DDS control chips PIC16F628A-1 and PIC16F628A-2 have written the VER4.06 program. After all the installation is completed, connect to the 5V power supply and adjust the contrast of the 10K potentiometer, which can be seen on the display under normal circumstances. If the characters are abnormal, please measure the working voltage of the MCU and the display. This setting has voltage polarity protection, so you will not burn your chip.
If the LCD cannot display characters, please try to exchange PIC16F628A, because the programs in the two chips are different, please install according to the number marked on the component by me.
5. DDS button description and operation steps:
1. Description of button interface:
ENC coding switch wiring pin
MEM storage mode conversion
VFO VFO A is converted to VFO B, or VFO B is converted to VFO A.
SSB work mode conversion, USB LSB AM CW cyclic conversion.
RIT Fine-tune the receiving frequency.
STEP Step adjustment button.
CAL Function setting button.
KB-1 and KB-2 both have a common pin, but it is not a ground wire. Please pay attention when installing.
3. Press and hold the CAL button, power on to enter the initial setting interface, and release the CAL button.
A: ENABLE 6XREFCLE: Set the chip clock mode, adjust the frequency encoding switch settings, AD9851 is set to 6 times the frequency, AD9850 is set to 1 times the frequency, short press CAL to enter the next content.
B: DDS-SYSTEM-CLK: Chip operating frequency setting, adjust the coding switch to change the value, adjust the step with the STEP key, AD9851 is set to 6 times the frequency of the active clock, and AD9850 is set to the actual output of the source clock. Value, short press CAL to enter the next content.
C: MIN_RX_DDS_FREQ: Minimum operating frequency setting, adjust the coding switch to change the value, and adjust the step with the STEP key. It should be set to be greater than the intermediate frequency value. Short press CAL to enter the next item.
D: MAX_RX_DDS_FREQ: Set the maximum operating frequency, adjust the coding switch to change the value, and adjust the step with the STEP key. It should be set to below 60MHZ. Short press CAL to enter the next item.
E: SSB_OFFSET: SSB working mode fine-tuning, adjust the coding switch to change the value, adjust the step with the STEP key, short press CAL to enter the next content.
F: CW_OFFSET: CW working mode fine-tuning, adjust the code switch to change the value, adjust the step with the STEP key, short press CAL to enter the next content.
G: OFFSET_FREQ: Intermediate frequency setting, such as 9MHZ or 10.7MHZ, adjust the code switch to change the value, adjust the step with the STEP key, and short press CAL to enter the next content.
H: MULTIPLIER: Multiplier setting, it should be set to 1. Short press CAL to enter the next content.
I: The display will prompt SAVE to automatically save the contents of the above temples and return to normal working status
Other matters needing attention:
1. DDS SYSTEM CLK After measuring the 30MHZ active crystal with a frequency counter, multiply the measured value by 6, and set the calculated value here. If you use AD9851, the initial setting is 180000000.
2. OFFSET FREQ Intermediate frequency setting can be set to + or -, rotate the coding switch to change the value, press and hold the STEP key, and then rotate the coding switch to adjust the step. In addition, the minimum operating frequency plus intermediate frequency must be greater than 0.
** ** Frequency storage **
Store the current VFO frequency: press and hold the MEM button for more than 1 second, and use the encoder to select the channel you want to store. While selecting, the original frequency of the selected channel will be displayed on the LCD. At this time, press and hold the MEM button again for more than 1 second. When returning to the VFO display, a message "SAVING" will be displayed briefly. (Stored) If you decide to return to the VFO display or not to store, tap the MEM button or wait for 10 seconds to return automatically. Before using the storage function, please confirm that all parameter settings are correct, which will prevent wrong information from being written into the channel.
** Use storage channel **
When changing from VFO state to MEM state, the encoder can select the previously stored receiving frequency,
Tap the MEM button, "MEM 1" will be displayed on the top of the LCD. You can use the encoder to select the channel you want to use. When in the MEM mode, the TX button and RPT button function normally, but you cannot change the frequency with the encoder. RIT functions normally. (You can use the encoder to change the RIT frequency). When in MEM mode, you cannot use the setup menu or frequency storage function.
During operation, the setting menu will check the correctness of the storage. If an error message is found, the "MEM" display will change to "---". The reason for this is when you change some parameters in the setting menu afterwards. Then try to store the previous changes. (For example: assuming ffice:smarttags" />30M receiving frequency is stored in MEN 1. If you reduce the MAX RX DDS FREQ frequency to 29M, when you try to use MEM 1, the setting menu will find that the 30M receiving frequency is wrong, because It is too high), therefore, the correct approach is to make the correct menu settings before storing the function.
There are two ways to exit MEM mode and return to VFO mode at the same time:
1) Tap the MEM button to ignore the memory frequency used.
2) Press and hold the MEM button for 1 second, the correct frequency will be copied to the VFO.
** Menu setting storage **
Any changes in the menu settings will be stored in the EEPROM after MULTIPLIER is set, and the "SAVING" message will be displayed briefly and return to the VFO state.
In the setting menu, (except the DDS REF FREQ menu), if the key, keyboard or encoder is inactive for 10 seconds, the screen will ignore all actions and return to the VFO display).
If RIT (fine adjustment) is pressed lightly, "RIT" will be displayed on the LCD, but its frequency will not change much, (range RX frequency +/-MAX_RIT_OFFSET frequency), press the RIT key again, the RIT display will disappear And return to RX frequency, and clear RIT frequency change at the same time.
If the RPT (REPEATER TX offset is only used for FM) function is enabled in the setup menu, tap RPT to display "-RPT" on the LCD, and at the same time, the (RPT OFFSET) frequency will be subtracted from the TX frequency. Press it again to clear the RPT setting. The default REPEATER TX OFFSET is 0KHZ, but it can be changed in the setting menu RPT OFFSET, ranging from 0 to 10MHZ. (It is also limited, because DDS has to set aside 0 to MAX DDS FREQ frequency)
If the RPT function is set to disabled, the RPT function is cancelled, and at the same time, the RPT setting frequency will be automatically set to 0HZ.
All settings will affect the frequency limit range, and at the same time confirm that the settings are valid, for example: TX offset plus RX frequency cannot exceed the DDS frequency range.
If the step button is pressed, a cursor will flash under the current frequency number. At this time, the encoder can be used to select the step.
For example: take 1KHZ as stepping, move the cursor to and release, then the change will be 1K as stepping, (if the rotation is too fast, the system will detect, if the stepping range is exceeded, the setting may remain unchanged.)
Any step setting in VFO state will be stored in EEPROM. (Not stored in the menu settings and RIT settings)
The frequency display will follow the following formula:
RX = MULTIPLIER x (RX_DDS_FREQ + OFFSET_FREQ)
TX = MULTIPLIER x (RX_DDS_FREQ + OFFSET_FREQ + TX_OFFSET_FREQ)
The frequency programmed into the DDS, is calculated as shown below.
RX = ABS(RX_DDS_FREQ)
TX = ABS(RX_DDS_FREQ + TX_OFFSET_FREQ)
RX_DDS_FREQ, MIN_RX_DDS_FREQ, MAX_RX_DDS_FREQ, TX_OFFSET_FREQ & OFFSET_FREQ
It can be positive or negative.
Here are a few different examples:
For example, the output frequency range of DDS is 30M to 40M:
MIN_RX_DDS_FREQ MAX_RX_DDS_FREQ OFFSET_FREQ RX Frequency display range.
To
30 MHZ 40 MHz 100 MHz = 130 MHz to 140 MHz. \ Note 1
30 MHZ 40 MHz -10 MHz = 20 MHz to 30 MHz. /
-40 MHZ -30 MHz 170 MHz = 140 MHz to 130 MHz. \ Note 2
-40 MHZ -30 MHz 60 MHz = 30 MHz to 20 MHz. /
DDS setting method used in FT180A
Display AD9851 common settings Explanation:
ENABLE RPT NO
X6 RECLK X6
DDS SYSTEM CLK 180M
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