# Failed to send a signal

**URL:** <https://discourse.myriadrf.org/t/failed-to-send-a-signal/7391>\
**Category:** Lime Suite\
**Created:** [5 November 2021 09:26 UTC](https://discourse.myriadrf.org/t/failed-to-send-a-signal/7391 "2021-11-05T09:26:22Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![Eve](https://avatars.discourse-cdn.com/v4/letter/e/9e8a1a/32.png) [@Eve](https://discourse.myriadrf.org/u/Eve)\
**Post date:** [5 November 2021 09:26 UTC](https://discourse.myriadrf.org/t/failed-to-send-a-signal/7391/1 "2021-11-05T09:26:23Z")

</div>

/\*\*  
@file basicTX.cpp  
@author Lime Microsystems ([www.limemicro.com](http://www.limemicro.com))  
@brief minimal TX example  
\*/  
#include   
#include   
#include \<math.h\>  
#include “lime/LimeSuite.h”

using namespace std;

//Device structure, should be initialize to NULL  
lms\_device\_t\* device = NULL;

int error()  
{  
if (device != NULL)  
LMS\_Close(device);  
exit(-1);  
}

int main(int argc, char\*\* argv)  
{  
const double frequency = 500e6; //center frequency to 500 MHz  
const double sample\_rate = 5e6; //sample rate to 5 MHz  
const double tone\_freq = 1e6; //tone frequency  
const double f\_ratio = tone\_freq/sample\_rate;  
//Find devices  
int n;  
lms\_info\_str\_t list[8]; //should be large enough to hold all detected devices  
if ((n = LMS\_GetDeviceList(list)) \< 0) //NULL can be passed to only get number of devices  
error();

```
cout << "Devices found: " << n << endl; //print number of devices
if (n < 1)
    return -1;

//open the first device
if (LMS_Open(&device, list[0], NULL))
    error();

//Initialize device with default configuration
//Do not use if you want to keep existing configuration
//Use LMS_LoadConfig(device, "/path/to/file.ini") to load config from INI
if (LMS_Init(device)!=0)
    error();

//Enable TX channel,Channels are numbered starting at 0
if (LMS_EnableChannel(device, LMS_CH_TX, 0, true)!=0)
    error();

//Set sample rate
if (LMS_SetSampleRate(device, sample_rate, 0)!=0)
    error();
cout << "Sample rate: " << sample_rate/1e6 << " MHz" << endl;

//Set center frequency
if (LMS_SetLOFrequency(device,LMS_CH_TX, 0, frequency)!=0)
    error();
cout << "Center frequency: " << frequency/1e6 << " MHz" << endl;

//select TX1_1 antenna
if (LMS_SetAntenna(device, LMS_CH_TX, 0, LMS_PATH_TX1)!=0)
    error();

//set TX gain
if (LMS_SetNormalizedGain(device, LMS_CH_TX, 0, 0.7) != 0)
    error();

//calibrate Tx, continue on failure
LMS_Calibrate(device, LMS_CH_TX, 0, sample_rate, 0);

//Streaming Setup

lms_stream_t tx_stream; //stream structure
tx_stream.channel = 0; //channel number
tx_stream.fifoSize = 256*1024; //fifo size in samples
tx_stream.throughputVsLatency = 0.5; //0 min latency, 1 max throughput
tx_stream.dataFmt = lms_stream_t::LMS_FMT_F32; //floating point samples
tx_stream.isTx = true; //TX channel
LMS_SetupStream(device, &tx_stream);

//Initialize data buffers
const int buffer_size = 1024*8;
float tx_buffer[2*buffer_size]; //buffer to hold complex values (2*samples))
for (int i = 0; i <buffer_size; i++) { //generate TX tone
    const double pi = acos(-1);
    double w = 2*pi*i*f_ratio;
    tx_buffer[2*i] = cos(w);
    tx_buffer[2*i+1] = sin(w);
}   
cout << "Tx tone frequency: " << tone_freq/1e6 << " MHz" << endl;

const int send_cnt = int(buffer_size*f_ratio) / f_ratio; 
cout << "sample count per send call: " << send_cnt << std::endl;

LMS_StartStream(&tx_stream); //Start streaming
//Streaming
auto t1 = chrono::high_resolution_clock::now();
auto t2 = t1;
while (chrono::high_resolution_clock::now() - t1 < chrono::seconds(10)) //run for 10 seconds
{
    //Transmit samples
    int ret = LMS_SendStream(&tx_stream, tx_buffer, send_cnt, nullptr, 1000);
    if (ret != send_cnt)
        cout << "error: samples sent: " << ret << "/" << send_cnt << endl;
    //Print data rate (once per second)
    if (chrono::high_resolution_clock::now() - t2 > chrono::seconds(1))
    {
        t2 = chrono::high_resolution_clock::now();
        lms_stream_status_t status;
        LMS_GetStreamStatus(&tx_stream, &status); //Get stream status
        cout << "TX data rate: " << status.linkRate / 1e6 << " MB/s\n"; //link data rate
    }
}
//Stop streaming
LMS_StopStream(&tx_stream);
LMS_DestroyStream(device, &tx_stream);

//Disable TX channel
if (LMS_EnableChannel(device, LMS_CH_TX, 0, false)!=0)
    error();

//Close device
if (LMS_Close(device)==0)
    cout << "Closed" << endl;
return 0;

```

}

---

<div class="post-metadata">

**Author:** ![andrewback](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@andrewback](https://discourse.myriadrf.org/u/andrewback)\
**Post date:** [5 November 2021 09:27 UTC](https://discourse.myriadrf.org/t/failed-to-send-a-signal/7391/2 "2021-11-05T09:27:03Z")

</div>

Can you provide a bit more info please.

---

<div class="post-metadata">

**Author:** ![Eve](https://avatars.discourse-cdn.com/v4/letter/e/9e8a1a/32.png) [@Eve](https://discourse.myriadrf.org/u/Eve)\
**Post date:** [8 November 2021 07:50 UTC](https://discourse.myriadrf.org/t/failed-to-send-a-signal/7391/3 "2021-11-08T07:50:59Z")

</div>

hardware:limesdr-pcie v1.3

Data can be successfully received and saved through LimeSuite API; But it cannot be emitted using the LimeSuite API alone;

---

<div class="post-metadata">

**Author:** ![andrewback](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@andrewback](https://discourse.myriadrf.org/u/andrewback)\
**Post date:** [9 November 2021 19:07 UTC](https://discourse.myriadrf.org/t/failed-to-send-a-signal/7391/4 "2021-11-09T19:07:24Z")

</div>

@Zack perhaps you or a colleague could take a look and advise.

---

<div class="post-metadata">

**Author:** ![Zack](https://yyz2.discourse-cdn.com/flex034/user_avatar/discourse.myriadrf.org/zack/32/89_2.png) [@Zack](https://discourse.myriadrf.org/u/Zack)\
**Post date:** [10 November 2021 07:27 UTC](https://discourse.myriadrf.org/t/failed-to-send-a-signal/7391/5 "2021-11-10T07:27:38Z")

</div>

Hi @Eve,  
Could you share output you get when trying to transmit data.

---

<div class="post-metadata">

**Author:** ![yt7pwr](https://avatars.discourse-cdn.com/v4/letter/y/ecd19e/32.png) [@yt7pwr](https://discourse.myriadrf.org/u/yt7pwr)\
**Post date:** [13 November 2021 08:41 UTC](https://discourse.myriadrf.org/t/failed-to-send-a-signal/7391/6 "2021-11-13T08:41:23Z")

</div>

I always configure both receiver and tramsitter. This is basicTX example modified for HF operation (21,768MHz) and LimeSDR-Mini.

/\*\*  
@file basicTX.cpp  
@author Lime Microsystems  
@brief minimal TX example

```
Modified by yt7pwr 22.6.2021
LimeSDR-Mini
NCO 9MHz
TX out 21.768MHz

```

\*/  
#include   
#include   
#include \<math.h\>  
#include “lime/LimeSuite.h”

using namespace std;

//Device structure, should be initialize to NULL  
lms\_device\_t\* device = NULL;

int error()  
{  
if (device != NULL)  
LMS\_Close(device);  
exit(-1);  
}

int main(int argc, char\*\* argv)  
{  
const double frequency = 30e6; // center frequency to 30MHz  
const double NCOfreq[16] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,9e6 }; // index 15, 9MHz  
const double sample\_rate = 3.072e6; // sample rate to 3.072MHz  
const double tone\_freq = 0.768e6; // tone frequency 768KHz from center 30MHz - NCO  
const double f\_ratio = tone\_freq / sample\_rate;  
const double pi = acos(-1);

```
//Find devices
int n;
lms_info_str_t list[8]; //should be large enough to hold all detected devices

if ((n = LMS_GetDeviceList(list)) < 0) //NULL can be passed to only get number of devices
	error();

cout << "Devices found: " << n << endl; //print number of devices
if (n < 1)
	return -1;

//open the first device
if (LMS_Open(&device, list[0], NULL))
	error();

//Initialize device with default configuration
//Do not use if you want to keep existing configuration
//Use LMS_LoadConfig(device, "/path/to/file.ini") to load config from INI

if (LMS_Init(device) != 0)
	error();

//Enable RX channel,Channels are numbered starting at 0
if (LMS_EnableChannel(device, LMS_CH_RX, 0, true) != 0)
	error();

//Enable TX channel,Channels are numbered starting at 0
if (LMS_EnableChannel(device, LMS_CH_TX, 0, true) != 0)
	error();

//Set sample rate
if (LMS_SetSampleRate(device, sample_rate, 0) != 0)
	error();
cout << "Sample rate: " << sample_rate / 1e6 << " MHz" << endl;

//Set center frequency
if (LMS_SetLOFrequency(device, LMS_CH_RX, 0, frequency) != 0) // set RX LO 30MHz
	error();
cout << "Center RX frequency: " << frequency / 1e6 << " MHz" << endl;

//Set center frequency
if (LMS_SetLOFrequency(device, LMS_CH_TX, 0, frequency) != 0) // set TX LO 30MHz
	error();
cout << "Center TX frequency: " << frequency / 1e6 << " MHz" << endl;

if (LMS_SetNCOFrequency(device, LMS_CH_RX, 0, NCOfreq, 0.0) != 0) // set RX NCO 9MHz
	error();
cout << "RX NCO frequency: " << NCOfreq[15] / 1e6 << " MHz" << endl;

if (LMS_SetNCOFrequency(device, LMS_CH_TX, 0, NCOfreq, 0.0) != 0) // set TX NCO 9MHz
	error();
cout << "TX NCO frequency: " << NCOfreq[15] / 1e6 << " MHz" << endl;

if (LMS_SetNCOIndex(device, LMS_CH_RX, 0, 15, false) != 0) // up converter
	error();
cout << "RX in frequency: " << (frequency - NCOfreq[15]) / 1e6 << " MHz" << endl;

if (LMS_SetNCOIndex(device, LMS_CH_TX, 0, 15, true) != 0) // down converter
	error();
cout << "TX out frequency: " << (frequency - NCOfreq[15]) / 1e6 << " MHz" << endl;

//select RX1 antenna, LNAW (change for LimeSDR-USB!)
if (LMS_SetAntenna(device, LMS_CH_RX, 0, LMS_PATH_LNAW) != 0)
	error();

//select TX1 antenna, PATH2 (change for LimeSDR-USB!)
if (LMS_SetAntenna(device, LMS_CH_TX, 0, LMS_PATH_TX2) != 0)
	error();

//set TX gain
if (LMS_SetNormalizedGain(device, LMS_CH_TX, 0, 1.0) != 0) // 100% output
	error();

if (LMS_SetLPFBW(device, LMS_CH_TX, 0, 60e6) != 0) // 60MHz LPF
	error();

//calibrate Rx, continue on failure
LMS_Calibrate(device, LMS_CH_RX, 0, 5e6, 0);

//calibrate Tx, continue on failure
LMS_Calibrate(device, LMS_CH_TX, 0, 5e6, 0);

// RX Streaming Setup    
lms_stream_t rx_stream; //stream structure
rx_stream.channel = 0; //channel number
rx_stream.fifoSize = 256 * 1024; //fifo size in samples
rx_stream.throughputVsLatency = 0.5; //0 min latency, 1 max throughput
rx_stream.dataFmt = lms_stream_t::LMS_FMT_F32; //floating point samples
rx_stream.isTx = false; //TX channel
LMS_SetupStream(device, &rx_stream);

// TX Streaming Setup    
lms_stream_t tx_stream; //stream structure
tx_stream.channel = 0; //channel number
tx_stream.fifoSize = 256 * 1024; //fifo size in samples
tx_stream.throughputVsLatency = 0.5; //0 min latency, 1 max throughput
tx_stream.dataFmt = lms_stream_t::LMS_FMT_F32; //floating point samples
tx_stream.isTx = true; //TX channel
LMS_SetupStream(device, &tx_stream);

//Initialize data buffers
const int buffer_size = 1024 * 32;
float tx_buffer[2 * buffer_size]; //buffer to hold complex values (2*samples))
float rx_buffer[2 * buffer_size]; //buffer to hold complex values (2*samples))
double phase = 2.0 * pi * f_ratio;

for (int i = 0; i < buffer_size; i++)
{ //generate TX tone
	double w = phase * i;
	tx_buffer[2 * i] = cos(w);
	tx_buffer[2 * i + 1] = sin(w);
}

cout << "Tx tone frequency: " << tone_freq / 1e6 << " MHz" << endl;

const int send_cnt = buffer_size;
const int receive_cnt = buffer_size;
cout << "sample count per send call: " << send_cnt << std::endl;

LMS_StartStream(&rx_stream); //	Start streaming RX
LMS_StartStream(&tx_stream); // Start streaming TX
//Streaming
auto t1 = chrono::high_resolution_clock::now();
auto t2 = t1;

while (chrono::high_resolution_clock::now() - t1 < chrono::seconds(10)) //run for 10 seconds
{
	LMS_RecvStream(&rx_stream, rx_buffer, receive_cnt, nullptr, 1000);
	//Transmit samples
	int ret = LMS_SendStream(&tx_stream, tx_buffer, send_cnt, nullptr, 1000);
	if (ret != send_cnt)
		cout << "error: samples sent: " << ret << "/" << send_cnt << endl;
	//Print data rate (once per second)
	if (chrono::high_resolution_clock::now() - t2 > chrono::seconds(1))
	{
		t2 = chrono::high_resolution_clock::now();
		lms_stream_status_t status;
		LMS_GetStreamStatus(&tx_stream, &status); //Get stream status
		cout << "TX data rate: " << status.linkRate / 1e6 << " MB/s\n"; //link data rate
	}
}

//Stop streaming
LMS_StopStream(&rx_stream);
LMS_StopStream(&tx_stream);
LMS_DestroyStream(device, &rx_stream);
LMS_DestroyStream(device, &tx_stream);

//Disable TX channel
if (LMS_EnableChannel(device, LMS_CH_TX, 0, false) != 0)
	error();

//Disable RX channel
if (LMS_EnableChannel(device, LMS_CH_RX, 0, false) != 0)
	error();

//Close device
if (LMS_Close(device) == 0)
	cout << "Closed" << endl;
return 0;

```

}